34 results on '"T. Schimek-Jasch"'
Search Results
2. Evaluation of prognostic factors after primary chemoradiotherapy of anal cancer: A multicenter study of the German Cancer Consortium-Radiation Oncology Group (DKTK-ROG)
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D. Martin, T. Schreckenbach, P. Ziegler, N. Filmann, G. Kalinauskaite, I. Tinhofer, V. Budach, C. Gani, D. Zips, T. Schimek-Jasch, H. Schäfer, A.L. Grosu, E. Thomas, M. Krause, H. Dapper, S. Combs, C. Hoffmann, M. Stuschke, F. Walter, C. Belka, I. Kurth, W.W Hadiwikarta, M. Baumann, C. Rödel, and E. Fokas
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Oncology ,Mitomycin ,Medizin ,Carcinoma, Squamous Cell ,Humans ,Radiology, Nuclear Medicine and imaging ,HIV Infections ,Hematology ,Chemoradiotherapy ,Anus Neoplasms ,Prognosis ,Retrospective Studies - Abstract
Prognosis after chemoradiotherapy (CRT) for anal squamous cell carcinoma (ASCC) shows marked differences among patients according to TNM subgroups, however individualized risk assessment tools to better stratify patients for treatment (de-) escalation or intensified follow-up are lacking in ASCC.Patients' data from eight sites of the German Cancer Consortium - Radiation Oncology Group (DKTK-ROG), comprising a total of 605 patients with ASCC, treated with standard definitive CRT with 5-FU/Mitomycin C or Capecitabine/Mitomycin C between 2004-2018, were used to evaluate prognostic factors based on Cox regression models for disease-free survival (DFS). Evaluated variables included age, gender, Karnofsky performance score (KPS), HIV-status, T-category, lymph node status and laboratory parameters. Multivariate cox models were separately constructed for the whole cohort and the subset of patients with early-stage (cT1-2 N0M0) tumors.After a median follow-up of 46 months, 3-year DFS for patients with early-stage ASCC was 84.9%, and 67.1% for patients with locally-advanced disease (HR 2.4, p 0.001). T-category (HR vs. T1: T2 2.02; T3 2.11; T4 3.03), N-category (HR versus N0: 1.8 for N1-3), age (HR 1.02 per year), and KPS (HR 0.8 per step) were significant predictors for DFS in multivariate analysis in the entire cohort. The model performed with a C-index of 0.68. In cT1-2N0 patients, T-category (HR 2.14), HIV status (HR 2.57), age (1.026 per year), KPS (HR 0.7 per step) and elevated platelets (HR 1.3 per 100/nl) were associated with worse DFS (C-index of 0.7).Classical clinicopathologic parameters like T-category, N-category, age and KPS remain to be significant prognostic factors for DFS in patients treated with contemporary CRT for ASCC. HIV and platelets were significantly associated with worse DFS in patients with early stage ASCC.
- Published
- 2021
3. PO-1556: 4D-PET radiomics-features for radiotherapy treatment monitoring in locally advanced NSCLC patients
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Tobias Fechter, Eleni Gkika, Dimos Baltas, A.L. Grosu, Ursula Nestle, G. Radicioni, Michael Mix, Sonja Adebahr, Matthias Benndorf, T. Schimek Jasch, and M. Carles
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medicine.medical_specialty ,Oncology ,Radiomics ,business.industry ,Locally advanced ,Medicine ,Radiology, Nuclear Medicine and imaging ,Radiotherapy treatment ,Hematology ,Radiology ,business - Published
- 2020
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4. Prognostic value of metabolic tumor volume on [ 18 F]FDG PET/CT in addition to the TNM classification system of locally advanced non-small cell lung cancer.
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Brose A, Miederer I, König J, Gkika E, Sahlmann J, Schimek-Jasch T, Schreckenberger M, Nestle U, Kappes J, and Miederer M
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- Adult, Aged, Aged, 80 and over, Female, Humans, Male, Middle Aged, Chemoradiotherapy, Prognosis, Radiopharmaceuticals, Retrospective Studies, Carcinoma, Non-Small-Cell Lung diagnostic imaging, Carcinoma, Non-Small-Cell Lung pathology, Carcinoma, Non-Small-Cell Lung therapy, Carcinoma, Non-Small-Cell Lung mortality, Carcinoma, Non-Small-Cell Lung metabolism, Fluorodeoxyglucose F18, Lung Neoplasms diagnostic imaging, Lung Neoplasms pathology, Lung Neoplasms therapy, Lung Neoplasms mortality, Neoplasm Staging, Positron Emission Tomography Computed Tomography methods, Tumor Burden
- Abstract
Purpose: Staging of non-small cell lung cancer (NSCLC) is commonly based on [
18 F]FDG PET/CT, in particular to exclude distant metastases and guide local therapy approaches like resection and radiotherapy. Although it is hoped that PET/CT will increase the value of primary staging compared to conventional imaging, it is generally limited to the characterization of TNM. The first aim of this study was to evaluate the PET parameter metabolic tumor volume (MTV) above liver background uptake as a prognostic marker in lung cancer. The second aim was to investigate the possibility of incorporating MTV into the TNM classification system for disease prognosis in locally advanced NSCLC treated with chemoradiotherapy., Methods: Retrospective evaluation of 235 patients with histologically proven, locally advanced NSCLC from the multi-centre randomized clinical PETPLAN trial and a clinical cohort from a hospital registry. The PET parameters SUVmax, SULpeak, MTV and TLG above liver background uptake were determined. Kaplan-Meier curves and stratified Cox proportional hazard regression models were used to investigate the prognostic value of PET parameters and TNM along with clinical variables. Subgroup analyses were performed to compare hazard ratios according to TNM, MTV, and the two variables combined., Results: In the multivariable Cox regression analysis, MTV was associated with significantly worse overall survival independent of stage and other prognostic variables. In locally advanced disease stages treated with chemoradiotherapy, higher MTV was significantly associated with worse survival (median 17 vs. 32 months). Using simple cut-off values (45 ml for stage IIIa, 48 ml for stage IIIb, and 105 ml for stage IIIc), MTV was able to further predict differences in survival for stages IIIa-c. The combination of TNM and MTV staging system showed better discrimination for overall survival in locally advanced disease stages, compared to TNM alone., Conclusion: Higher metabolic tumor volume is significantly associated with worse overall survival and combined with TNM staging, it provides more precise information about the disease prognosis in locally advanced NSCLC treated with chemoradiotherapy compared to TNM alone. As a PET parameter with volumetric information, MTV represents a useful addition to TNM., Competing Interests: Declarations. Ethics approval and consent to participate: This study was approved by the Institutional Ethics Committee in addition to the main trial for the PET Plan cohort (ARO-2009-09) and approval was waived by the competent Ethic committee for the clinical cohort. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)- Published
- 2024
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5. Impact of mediastinal tumor burden and lymphatic spread in locally advanced non-small-cell lung cancer: A secondary analysis of the multicenter randomized PET-Plan trial.
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Gkika E, Dejonckheere CS, Sahlmann J, Barth SA, Schimek-Jasch T, Adebahr S, Hecht M, Miederer M, Brose A, Binder H, König J, Grosu AL, Nestle U, and Rimner A
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- Humans, Male, Female, Middle Aged, Aged, Prospective Studies, Adult, Mediastinal Neoplasms diagnostic imaging, Mediastinal Neoplasms radiotherapy, Mediastinal Neoplasms therapy, Mediastinal Neoplasms pathology, Mediastinal Neoplasms mortality, Fluorodeoxyglucose F18, Chemoradiotherapy, Radiopharmaceuticals, Aged, 80 and over, Lymph Nodes pathology, Lymph Nodes diagnostic imaging, Carcinoma, Non-Small-Cell Lung pathology, Carcinoma, Non-Small-Cell Lung diagnostic imaging, Carcinoma, Non-Small-Cell Lung radiotherapy, Carcinoma, Non-Small-Cell Lung therapy, Carcinoma, Non-Small-Cell Lung mortality, Lung Neoplasms pathology, Lung Neoplasms diagnostic imaging, Lung Neoplasms therapy, Lung Neoplasms radiotherapy, Lung Neoplasms mortality, Positron Emission Tomography Computed Tomography methods, Lymphatic Metastasis, Tumor Burden
- Abstract
Purpose: The aim of this secondary analysis of the prospective randomized phase 2 PET-Plan trial (ARO-2009-09; NCT00697333) was to evaluate the impact of mediastinal tumor burden and lymphatic spread in patients with locally advanced non-small-cell lung cancer (NSCLC)., Methods: All patients treated per protocol (n = 172) were included. Patients received isotoxically dose-escalated chemoradiotherapy up to a total dose of 60-74 Gy in 30-37 fractions, aiming as high as possible while adhering to normal tissue constraints. Radiation treatment (RT) planning was based on an
18 F-FDG PET/CT targeting all lymph node (LN) stations containing CT positive LNs (i.e. short axis diameter > 10 mm), even if PET-negative (arm A) or targeting only LN stations containing PET-positive nodes (arm B). LN stations were classified into echelon 1 (ipsilateral hilum), 2 (ipsilateral station 4 and 7), and 3 (rest of the mediastinum, contralateral hilum). The endpoints were overall survival (OS), progression-free survival (PFS), and freedom from local progression (FFLP)., Results: The median follow-up time (95 % confidence interval [CI]) was 41.1 (33.8 - 50.4) months. Patients with a high absolute number of PET-positive LN stations had worse OS (hazard ratio [HR] = 1.09; 95 % CI 0.99 - 1.18; p = 0.05) and PFS (HR = 1.12; 95 % CI 1.04 - 1.20; p = 0.003), irrespective of treatment arm allocation. The prescribed RT dose to the LNs did not correlate with any of the endpoints when considering all patients. However, in patients in arm B (i.e., PET-based selective nodal irradiation), prescribed RT dose to each LN station correlated significantly with FFLP (HR=0.45; 95 % CI 0.24-0.85; p = 0.01). Furthermore, patients with involvement of echelon 3 LN stations had worse PFS (HR = 2.22; 95 % CI 1.16-4.28; p = 0.02), also irrespective of allocation., Conclusion: Mediastinal tumor burden and lymphatic involvement patterns influence outcome in patients treated with definitive chemoradiotherapy for locally advanced NSCLC. Higher dose to LNs did not improve OS, but did improve FFLP in patients treated with PET-based dose-escalated RT., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [MM reports consultant fees from Novartis, Roche, Telix, and Veraxa. The other authors have no relevant financial or non-financial interests to disclose.]., (Copyright © 2024. Published by Elsevier B.V.)- Published
- 2024
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6. Stereotactic Body Radiotherapy for Centrally Located Inoperable Early-Stage NSCLC: EORTC 22113-08113 LungTech Phase II Trial Results.
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Levy A, Adebahr S, Hurkmans C, Ahmed M, Ahmad S, Guckenberger M, Geets X, Lievens Y, Lambrecht M, Pourel N, Lewitzki V, Konopa K, Franks K, Dziadziuszko R, McDonald F, Fortpied C, Clementel E, Fournier B, Rizzo S, Fink C, Riesterer O, Peulen H, Andratschke N, McWilliam A, Gkika E, Schimek-Jasch T, Grosu AL, Le Pechoux C, Faivre-Finn C, and Nestle U
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- Humans, Male, Female, Aged, Middle Aged, Aged, 80 and over, Prospective Studies, Neoplasm Staging, Radiosurgery methods, Carcinoma, Non-Small-Cell Lung pathology, Carcinoma, Non-Small-Cell Lung radiotherapy, Carcinoma, Non-Small-Cell Lung surgery, Lung Neoplasms pathology, Lung Neoplasms radiotherapy, Lung Neoplasms surgery
- Abstract
Introduction: The international phase II single-arm LungTech trial 22113-08113 of the European Organization for Research and Treatment of Cancer assessed the safety and efficacy of stereotactic body radiotherapy (SBRT) in patients with centrally located early-stage NSCLC., Methods: Patients with inoperable non-metastatic central NSCLC (T1-T3 N0 M0, ≤7cm) were included. After prospective central imaging review and radiation therapy quality assurance for any eligible patient, SBRT (8 × 7.5 Gy) was delivered. The primary endpoint was freedom from local progression probability three years after the start of SBRT., Results: The trial was closed early due to poor accrual related to repeated safety-related pauses in recruitment. Between August 2015 and December 2017, 39 patients from six European countries were included and 31 were treated per protocol and analyzed. Patients were mainly male (58%) with a median age of 75 years. Baseline comorbidities were mainly respiratory (68%) and cardiac (48%). Median tumor size was 2.6 cm (range 1.2-5.5) and most cancers were T1 (51.6%) or T2a (38.7%) N0 M0 and of squamous cell origin (48.4%). Six patients (19.4%) had an ultracentral tumor location. The median follow-up was 3.6 years. The rates of 3-year freedom from local progression and overall survival were 81.5% (90% confidence interval [CI]: 62.7%-91.4%) and 61.1% (90% CI: 44.1%-74.4%), respectively. Cumulative incidence rates of local, regional, and distant progression at three years were 6.7% (90% CI: 1.6%-17.1%), 3.3% (90% CI: 0.4%-12.4%), and 29.8% (90% CI: 16.8%-44.1%), respectively. SBRT-related acute adverse events and late adverse events ≥ G3 were reported in 6.5% (n = 2, including one G5 pneumonitis in a patient with prior interstitial lung disease) and 19.4% (n = 6, including one lethal hemoptysis after a lung biopsy in a patient receiving anticoagulants), respectively., Conclusions: The LungTech trial suggests that SBRT with 8 × 7.5Gy for central lung tumors in inoperable patients is associated with acceptable local control rates. However, late severe adverse events may occur after completion of treatment. This SBRT regimen is a viable treatment option after a thorough risk-benefit discussion with patients. To minimize potentially fatal toxicity, careful management of dose constraints, and post-SBRT interventions is crucial., Competing Interests: Disclosure Dr. Levy reports academic funding from Roche, Beigene, AstraZeneca, and Pharmamar. Dr. Adebahr was supported by the German Cancer Consortium (DKTK) and is now supported by a grant from the Federal Ministry of Education and Research (BMBF). The remaining authors declare no conflict of interest., (Copyright © 2024 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.)
- Published
- 2024
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7. Cardiac Function Modifies the Impact of Heart Base Dose on Survival: A Voxel-Wise Analysis of Patients With Lung Cancer From the PET-Plan Trial.
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Craddock M, Nestle U, Koenig J, Schimek-Jasch T, Kremp S, Lenz S, Banfill K, Davey A, Price G, Salem A, Faivre-Finn C, van Herk M, and McWilliam A
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- Humans, Stroke Volume, Tomography, X-Ray Computed, Ventricular Function, Left, Positron-Emission Tomography, Lung Neoplasms diagnostic imaging, Lung Neoplasms radiotherapy, Carcinoma, Non-Small-Cell Lung diagnostic imaging, Carcinoma, Non-Small-Cell Lung radiotherapy
- Abstract
Introduction: Heart dose has emerged as an independent predictor of overall survival in patients with NSCLC treated with radiotherapy. Several studies have identified the base of the heart as a region of enhanced dose sensitivity and a potential target for cardiac sparing. We present a dosimetric analysis of overall survival in the multicenter, randomized PET-Plan trial (NCT00697333) and for the first time include left ventricular ejection fraction (EF) at baseline as a metric of cardiac function., Methods: A total of 205 patients with inoperable stage II or III NSCLC treated with 60 to 72 Gy in 2 Gy fractions were included in this study. A voxel-wise image-based data mining methodology was used to identify anatomical regions where higher dose was significantly associated with worse overall survival. Univariable and multivariable Cox proportional hazards models tested the association of survival with dose to the identified region, established prognostic factors, and baseline cardiac function., Results: A total of 172 patients remained after processing and censoring for follow-up. At 2-years posttreatment, a highly significant region was identified within the base of the heart (p < 0.005), centered on the origin of the left coronary artery and the region of the atrioventricular node. In multivariable analysis, the number of positron emission tomography-positive nodes (p = 0.02, hazard ratio = 1.13, 95% confidence interval: 1.02-1.25) and mean dose to the cardiac subregion (p = 0.02, hazard ratio = 1.11 Gy
-1 , 95% confidence interval: 1.02-1.21) were significantly associated with overall survival. There was a significant interaction between EF and region dose (p = 0.04) for survival, with contrast plots revealing a larger effect of region dose on survival in patients with lower EF values., Conclusions: This work validates previous image-based data mining studies by revealing a strong association between dose to the base of the heart and overall survival. For the first time, an interaction between baseline cardiac health and heart base dose was identified, potentially suggesting preexisting cardiac dysfunction exacerbates the impact of heart dose on survival., (Copyright © 2022 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.)- Published
- 2023
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8. Evaluation of prognostic factors after primary chemoradiotherapy of anal cancer: A multicenter study of the German Cancer Consortium-Radiation Oncology Group (DKTK-ROG).
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Martin D, Schreckenbach T, Ziegler P, Filmann N, Kalinauskaite G, Tinhofer I, Budach V, Gani C, Zips D, Schimek-Jasch T, Schäfer H, Grosu AL, Thomas E, Krause M, Dapper H, Combs S, Hoffmann C, Stuschke M, Walter F, Belka C, Kurth I, Hadiwikarta WW, Baumann M, Rödel C, and Fokas E
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- HIV Infections drug therapy, HIV Infections etiology, Humans, Mitomycin, Prognosis, Retrospective Studies, Anus Neoplasms therapy, Carcinoma, Squamous Cell therapy, Chemoradiotherapy
- Abstract
Background and Purpose: Prognosis after chemoradiotherapy (CRT) for anal squamous cell carcinoma (ASCC) shows marked differences among patients according to TNM subgroups, however individualized risk assessment tools to better stratify patients for treatment (de-) escalation or intensified follow-up are lacking in ASCC., Materials and Methods: Patients' data from eight sites of the German Cancer Consortium - Radiation Oncology Group (DKTK-ROG), comprising a total of 605 patients with ASCC, treated with standard definitive CRT with 5-FU/Mitomycin C or Capecitabine/Mitomycin C between 2004-2018, were used to evaluate prognostic factors based on Cox regression models for disease-free survival (DFS). Evaluated variables included age, gender, Karnofsky performance score (KPS), HIV-status, T-category, lymph node status and laboratory parameters. Multivariate cox models were separately constructed for the whole cohort and the subset of patients with early-stage (cT1-2 N0M0) tumors., Results: After a median follow-up of 46 months, 3-year DFS for patients with early-stage ASCC was 84.9%, and 67.1% for patients with locally-advanced disease (HR 2.4, p < 0.001). T-category (HR vs. T1: T2 2.02; T3 2.11; T4 3.03), N-category (HR versus N0: 1.8 for N1-3), age (HR 1.02 per year), and KPS (HR 0.8 per step) were significant predictors for DFS in multivariate analysis in the entire cohort. The model performed with a C-index of 0.68. In cT1-2N0 patients, T-category (HR 2.14), HIV status (HR 2.57), age (1.026 per year), KPS (HR 0.7 per step) and elevated platelets (HR 1.3 per 100/nl) were associated with worse DFS (C-index of 0.7)., Conclusion: Classical clinicopathologic parameters like T-category, N-category, age and KPS remain to be significant prognostic factors for DFS in patients treated with contemporary CRT for ASCC. HIV and platelets were significantly associated with worse DFS in patients with early stage ASCC., (Copyright © 2022 Elsevier B.V. All rights reserved.)
- Published
- 2022
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9. Changes in Blood Biomarkers of Angiogenesis and Immune Modulation after Radiation Therapy and Their Association with Outcomes in Thoracic Malignancies.
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Gkika E, Adebahr S, Brenner A, Schimek-Jasch T, Radicioni G, Exner JP, Rühle A, Spohn SKB, Popp I, Zamboglou C, Sprave T, Firat E, Niedermann G, Nicolay NH, Nestle U, Grosu AL, and Duda DG
- Abstract
The effects of radiotherapy on systemic immunity remain to be fully characterized in a disease-specific manner. The aim of the study was to examine potential biomarkers of systemic immunomodulation when using radiotherapy for thoracic malignancies. Serial blood samples were collected from 56 patients with thoracic malignancies prior (RTbaseline), during (RTduring) and at the end of radiotherapy (RTend), as well as at the first (FU1) and second follow-up (FU2). The changes in serum levels of IL-10, IFN-γ, IL-12p70, IL-13, IL-1β, IL-4, IL-6, IL-8, TNF-α, bFGF, sFlt-1, PlGF, VEGF, VEGF-C, VEGF-D and HGF were measured by multiplexed array and tested for associations with clinical outcomes. We observed an increase in the levels of IL-10, IFN-γ, PlGF and VEGF-D and a decrease in those of IL-8, VEGF, VEGF-C and sFlt-1 during and at the end of radiotherapy. Furthermore, baseline concentration of TNF-α significantly correlated with OS. IL-6 level at RTend and FU1,2 correlated with OS (RTend: p = 0.039, HR: 1.041, 95% CI: 1.002-1.082, FU1: p = 0.001, HR: 1.139, 95% CI: 1.056-1.228, FU2: p = 0.017, HR: 1.101 95% CI: 1.018-1.192), while IL-8 level correlated with OS at RTduring and RTend (RTduring: p = 0.017, HR: 1.014, 95% CI: 1.002-1.026, RTend: p = 0.004, HR: 1.007, 95% CI: 1.061-1.686). In conclusion, serum levels of TNF-α, IL-6 and IL-8 are potential biomarkers of response to radiotherapy. Given the recent implementation of immunotherapy in lung and esophageal cancer, these putative blood biomarkers should be further validated and evaluated in the combination or sequential therapy setting.
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- 2021
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10. Impact of radiotherapy protocol adherence in NSCLC patients treated with concurrent chemoradiation: RTQA results of the PET-Plan trial.
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Gkika E, Schimek-Jasch T, Kremp S, Lenz S, Stockinger M, Schaefer-Schuler A, Mix M, Küsters A, Tosch M, Hehr T, Eschmann SM, Bultel YP, Hass P, Fleckenstein J, Thieme AH, Dieckmann K, Miederer M, Holl G, Rischke HC, Adebahr S, König J, Binder H, Grosu AL, and Nestle U
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- Chemoradiotherapy, Humans, Positron-Emission Tomography, Prospective Studies, Carcinoma, Non-Small-Cell Lung therapy, Lung Neoplasms therapy
- Abstract
Introduction: The success of intensification and personalisation of the curative treatment of non-small cell lung cancer (NSCLC) is strongly associated with the precision in radiotherapy. Here, we evaluate the impact of radiotherapy protocol adherence in a prospective multicentre trial., Methods: In the open-label, randomised, controlled PET-Plan trial, patients with inoperable NSCLC were randomized at a 1:1 ratio regarding the target volume delineation informed by
1 F-FDG PET and CT plus elective nodal irradiation (arm A) or target volumes informed by PET alone (arm B) and received iso-toxically dose-escalated concurrent chemoradiation. The prospectively organised quality assurance program (RTQA) included individual case review by predefined criteria. For evaluation, protocol adherence was scored as per protocol (pP), with minor (miD), intermediate (inD) and major (maD) deviations. In order to exclude biases through patients who discontinued treatment, patients who received ≥60 Gy were additionally analysed., Results: Between 05/2009-11/2016, 205 patients were randomized, 204 patients started treatment according to protocol of which 31 (15%) patients had maD. Patients with maD had an inferior overall survival (OS) (HR 2.9, 95% CI 1.8-4.4, p < 0.0001) and a higher risk of loco-regional progression (HR 5.7, 95% CI 2.7-11.1, p < 0.0001). These results were significant also in the subgroup of patients receiving ≥ 60 Gy. Patients with maD concerning normal tissue delineation and/or dose constraints had a worse OS (p = 0.006) although no higher incidence of grade ≥ 3 toxicities., Conclusions: Non-adherence to the radiotherapy protocol was associated with an inferior OS and loco-regional control. These results underline the importance of RTQA., (Copyright © 2021. Published by Elsevier B.V.)- Published
- 2021
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11. FET-PET radiomics in recurrent glioblastoma: prognostic value for outcome after re-irradiation?
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Carles M, Popp I, Starke MM, Mix M, Urbach H, Schimek-Jasch T, Eckert F, Niyazi M, Baltas D, and Grosu AL
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- Adult, Aged, Female, Glioblastoma pathology, Humans, Male, Middle Aged, Prognosis, Prospective Studies, Radiopharmaceuticals therapeutic use, Treatment Outcome, Tyrosine therapeutic use, Glioblastoma diagnostic imaging, Glioblastoma radiotherapy, Neoplasm Recurrence, Local, Positron-Emission Tomography methods, Re-Irradiation, Tyrosine analogs & derivatives
- Abstract
Purpose: The value of O-(2-[18F]fluoroethyl)-L-tyrosine (FET)-positron emission tomography (PET)-radiomics in the outcome assessment of patients with recurrent glioblastoma (rGBM) has not been evaluated until now. The aim of this study was to evaluate whether a prognostic model based on FET-PET radiomics features (RF) is feasible and can identify rGBM patients that would most benefit from re-irradiation., Methods: We prospectively recruited rGBM patients who underwent FET-PET before re-irradiation (GLIAA-Pilot trial, DRKS00000633). Tumor volume was delineated using a semi-automatic method with a threshold of 1.8 times the standardized-uptake-value of the background. 135 FET-RF (histogram parameters, shape and texture features) were extracted. The analysis involved the characterization of tumor and non-tumor tissue with FET-RF and the evaluation of the prognostic value of FET-RF for time-to-progression (TTP), overall survival (OS) and recurrence location (RL)., Results: Thirty-two rGBM patients constituted our cohort. FET-RF discriminated significantly between tumor and non-tumor. The texture feature Small-Zone-Low-Gray-Level-Emphasis (SZLGE) showed the best performance for the prediction of TTP (p = 0.001, satisfying Bonferroni-multiple-test significance level). Additionally, two radiomics signatures could predict TTP (TTP-radiomics-signature, p = 0.001) and OS (OS-radiomics-signature, p = 0.038). SZLGE and the TTP-radiomics-signature additionally predicted RL. Specifically, high values for TTP-radiomics-signature and for SZLGE indicated not only earlier progression, but also a RL within the initial FET-PET active volume., Conclusion: Our findings suggest that FET-PET radiomics could contribute to the prognostic assessment and selection of rGBM-patients benefiting from re-irradiation. Trial registration DRKS00000633. Registered on 8th of December in 2010. https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00000633 .
- Published
- 2021
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12. FDG-PET Radiomics for Response Monitoring in Non-Small-Cell Lung Cancer Treated with Radiation Therapy.
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Carles M, Fechter T, Radicioni G, Schimek-Jasch T, Adebahr S, Zamboglou C, Nicolay NH, Martí-Bonmatí L, Nestle U, Grosu AL, Baltas D, Mix M, and Gkika E
- Abstract
The aim of this study is to identify clinically relevant image feature (IF) changes during chemoradiation and evaluate their efficacy in predicting treatment response. Patients with non-small-cell lung cancer (NSCLC) were enrolled in two prospective trials (STRIPE, PET-Plan). We evaluated 48 patients who underwent static (3D) and retrospectively-respiratory-gated 4D PET/CT scans before treatment and a 3D scan during or after treatment. Our proposed method rejects IF changes due to intrinsic variability. The IF variability observed across 4D PET is employed as a patient individualized normalization factor to emphasize statistically relevant IF changes during treatment. Predictions of overall survival (OS), local recurrence (LR) and distant metastasis (DM) were evaluated. From 135 IFs, only 17 satisfied the required criteria of being normally distributed across 4D PET and robust between 3D and 4D images. Changes during treatment in the area-under-the-curve of the cumulative standard-uptake-value histogram (δ
AUC ) within primary tumor discriminated (AUC = 0.87, Specificity = 0.78) patients with and without LR. The resulted prognostic model was validated with a different segmentation method (AUC = 0.83) and in a different patient cohort (AUC = 0.63). The quantification of tumor FDG heterogeneity by δCSH AUC during chemoradiation correlated with the incidence of local recurrence and might be recommended for monitoring treatment response in patients with NSCLC.CSH - Published
- 2021
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13. Efficacy and Toxicity of Different Chemotherapy Protocols for Concurrent Chemoradiation in Non-Small Cell Lung Cancer-A Secondary Analysis of the PET Plan Trial.
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Gkika E, Lenz S, Schimek-Jasch T, Waller CF, Kremp S, Schaefer-Schuler A, Mix M, Küsters A, Tosch M, Hehr T, Eschmann SM, Bultel YP, Hass P, Fleckenstein J, Thieme AH, Stockinger M, Dieckmann K, Miederer M, Holl G, Rischke HC, Adebahr S, König J, Binder H, Grosu AL, and Nestle U
- Abstract
(1) Background: The optimal chemotherapy (CHT) regimen for concurrent chemoradiation (cCRT) is not well defined. In this secondary analysis of the international randomized PET-Plan trial, we evaluate the efficacy of different CHT. (2) Methods: Patients with inoperable NSCLC were randomized at a 1:1 ratio regarding the target volume definition and received isotoxically dose-escalated cCRT using cisplatin 80 mg/m
2 (day 1, 22) and vinorelbin 15 mg/m2 (day 1, 8, 22, 29) (P1) or cisplatin 20 mg/m2 (day 1-5, 29-33) and vinorelbin 12.5 mg/m2 (day 1, 8, 15, 29, 36, 43) (P2) or carboplatin AUC1 (day 1-5, 29-33) and vinorelbin 12.5 mg/m2 (day 1, 8, 15, 29, 36, 43) (P3) or other CHT at the treating physician's discretion. (3) Results: Between 05/2009 and 11/2016, 205 patients were randomized and 172 included in the per-protocol analysis. Patients treated in P1 or P2 had a better overall survival (OS) compared to P3 ( p = 0.015, p = 0.01, respectively). Patients treated with carboplatin had a worse OS compared to cisplatin (HR 1.78, p = 0.03), but the difference did not remain significant after adjusting for age, ECOG, cardiac function creatinine and completeness of CHT. (4) Conclusions: Carboplatin doublets show no significant difference compared to cisplatin, after adjusting for possibly relevant factors, probably due to existing selection bias.- Published
- 2020
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14. Immunohistochemistry and Radiomic Features for Survival Prediction in Small Cell Lung Cancer.
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Gkika E, Benndorf M, Oerther B, Mohammad F, Beitinger S, Adebahr S, Carles M, Schimek-Jasch T, Zamboglou C, Frye BC, Bamberg F, Waller CF, Werner M, Grosu AL, Nestle U, and Kayser G
- Abstract
Background: The aim of the study was to evaluate the role of different immunohistochemical and radiomics features in patients with small cell lung cancer (SCLC). Methods: Consecutive patients with histologically proven SCLC with limited ( n = 47, 48%) or extensive disease ( n = 51, 52%) treated with radiotherapy and chemotherapy at our department were included in the analysis. The expression of different immunohistochemical markers from the initial tissue biopsy, such as CD56, CD44, chromogranin A, synaptophysin, TTF-1, GLUT-1, Hif-1 a, PD-1, and PD-L1, and MIB-1/KI-67 as well as LDH und NSE from the initial blood sample were evaluated. H-scores were additionally generated for CD44, Hif-1a, and GLUT-1. A total of 72 computer tomography (CT) radiomics texture features from a homogenous subgroup ( n = 31) of patients were correlated with the immunohistochemistry, the survival (OS), and the progression-free survival (PFS). Results: The median OS, calculated from diagnosis, was 21 months for patients with limited disease and 13 months for patients with extensive disease. The expression of synaptophysin correlated with a better OS (HR 0.546 95% CI 0.308-0.966, p = 0.03). The expression of TTF-1 (HR 0.286, 95% CI: 0.117-0.698, p = 0.006) and a lower GLUT-1 H-score (median = 50, HR: 0.511, 95% CI: 0.260-1.003, p = 0.05) correlated with a better PFS. Patients without chromogranin A expression had a higher risk for developing cerebral metastases ( p = 0.02) and patients with PD 1 expression were at risk for developing metastases ( p = 0.02). Our radiomics analysis did not reveal a single texture feature that correlated highly with OS or PFS. Correlation coefficients ranged between -0.48 and 0.39 for OS and between -0.46 and 0.38 for PFS. Conclusions: The role of synaptophysin should be further evaluated as synaptophysin-negative patients might profit from treatment intensification. We report an, at most, moderate correlation of radiomics features with overall and progression free survival and no correlation with the expression of different immunohistochemical markers., (Copyright © 2020 Gkika, Benndorf, Oerther, Mohammad, Beitinger, Adebahr, Carles, Schimek-Jasch, Zamboglou, Frye, Bamberg, Waller, Werner, Grosu, Nestle and Kayser.)
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- 2020
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15. Quality of life after pulmonary stereotactic fractionated radiotherapy (SBRT): Results of the phase II STRIPE trial.
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Nestle U, Adebahr S, Kaier K, Gkika E, Schimek-Jasch T, Hechtner M, Momm F, Gaertner J, Becker G, and Grosu AL
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- Dose Fractionation, Radiation, Humans, Prospective Studies, Quality of Life, Lung Neoplasms radiotherapy, Lung Neoplasms surgery, Radiosurgery adverse effects
- Abstract
Background and Purpose: Preserving health related quality of life (HRQOL) plays an important role in considering stereotactic body fractionated radiotherapy (SBRT). The prospective monocenter phase II STRIPE trial investigated long-term HRQOL after SBRT, efficacy and toxicity., Materials and Methods: Patients with ≤2 pulmonary lesions ≤5 cm were treated with 4DPET/CT-based SBRT (3 × 12.5 Gy or risk-adapted 5 × 7 Gy, to 60% isodose). Follow up (FU) was performed 2 and 7 weeks after SBRT, then 3-monthly for 2 years with assessment of response (primary endpoint: 2-year cumulative incidence of local progression (LP); secondary endpoints: local progression free survival (LPFS), overall survival (OS) and toxicity (CTCAE)). Impact of predefined patient and treatment related factors on HRQOL (EORTC QLQ-C30 and EORTC QLQ-LC13) was evaluated., Results: Between 02/2011 and 11/2014, 100 patients were given SBRT for 56 NSCLC and 44 pulmonary metastases (M1). Long-term FU overall revealed stable Quality of Life (QoL)/Global health status (GHS), functions-scores and symptoms. For QoL/GHS, patients with low (
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- 2020
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16. Less is more? Imaging-based target volume reduction - Authors' reply.
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Nestle U, Schimek-Jasch T, and König J
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- Chemoradiotherapy, Humans, Positron-Emission Tomography, Carcinoma, Non-Small-Cell Lung, Lung Neoplasms
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- 2020
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17. Imaging-based target volume reduction in chemoradiotherapy for locally advanced non-small-cell lung cancer (PET-Plan): a multicentre, open-label, randomised, controlled trial.
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Nestle U, Schimek-Jasch T, Kremp S, Schaefer-Schuler A, Mix M, Küsters A, Tosch M, Hehr T, Eschmann SM, Bultel YP, Hass P, Fleckenstein J, Thieme A, Stockinger M, Dieckmann K, Miederer M, Holl G, Rischke HC, Gkika E, Adebahr S, König J, and Grosu AL
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- Aged, Carcinoma, Non-Small-Cell Lung pathology, Female, Humans, Lung Neoplasms pathology, Male, Middle Aged, Neoplasm Staging, Carcinoma, Non-Small-Cell Lung diagnostic imaging, Carcinoma, Non-Small-Cell Lung therapy, Chemoradiotherapy, Fluorodeoxyglucose F18, Lung Neoplasms diagnostic imaging, Lung Neoplasms therapy, Positron Emission Tomography Computed Tomography, Radiopharmaceuticals
- Abstract
Background: With increasingly precise radiotherapy and advanced medical imaging, the concept of radiotherapy target volume planning might be redefined with the aim of improving outcomes. We aimed to investigate whether target volume reduction is feasible and effective compared with conventional planning in the context of radical chemoradiotherapy for patients with locally advanced non-small-cell lung cancer., Methods: We did a multicentre, open-label, randomised, controlled trial (PET-Plan; ARO-2009-09) in 24 centres in Austria, Germany, and Switzerland. Previously untreated patients (aged older than 18 years) with inoperable locally advanced non-small-cell lung cancer suitable for chemoradiotherapy and an Eastern Cooperative Oncology Group performance status of less than 3 were included. Undergoing
18 F-fluorodeoxyglucose (18 F-FDG) PET and CT for treatment planning, patients were randomly assigned (1:1) using a random number generator and block sizes between four and six to target volume delineation informed by18 F-FDG PET and CT plus elective nodal irradiation (conventional target group) or target volumes informed by PET alone (18 F-FDG PET-based target group). Randomisation was stratified by centre and Union for International Cancer Control stage. In both groups, dose-escalated radiotherapy (60-74 Gy, 2 Gy per fraction) was planned to the respective target volumes and applied with concurrent platinum-based chemotherapy. The primary endpoint was time to locoregional progression from randomisation with the objective to test non-inferiority of18 F-FDG PET-based planning with a prespecified hazard ratio (HR) margin of 1·25. The per-protocol set was included in the primary analysis. The safety set included all patients receiving any study-specific treatment. Patients and study staff were not masked to treatment assignment. This study is registered with ClinicalTrials.gov, NCT00697333., Findings: From May 13, 2009, to Dec 5, 2016, 205 of 311 recruited patients were randomly assigned to the conventional target group (n=99) or the18 F-FDG PET-based target group (n=106; the intention-to-treat set), and 172 patients were treated per protocol (84 patients in the conventional target group and 88 in the18 F-FDG PET-based target group). At a median follow-up of 29 months (IQR 9-54), the risk of locoregional progression in the18 F-FDG PET-based target group was non-inferior to, and in fact lower than, that in the conventional target group in the per-protocol set (14% [95% CI 5-21] vs 29% [17-38] at 1 year; HR 0·57 [95% CI 0·30-1·06]). The risk of locoregional progression in the18 F-FDG PET-based target group was also non-inferior to that in the conventional target group in the intention-to-treat set (17% [95% CI 9-24] vs 30% [20-39] at 1 year; HR 0·64 [95% CI 0·37-1·10]). The most common acute grade 3 or worse toxicity was oesophagitis or dysphagia (16 [16%] of 99 patients in the conventional target group vs 17 [16%] of 105 patients in the18 F-FDG PET-based target group); the most common late toxicities were lung-related (12 [12%] vs 11 [10%]). 20 deaths potentially related to study treatment were reported (seven vs 13)., Interpretation:18 F-FDG PET-based planning could potentially improve local control and does not seem to increase toxicity in patients with chemoradiotherapy-treated locally advanced non-small-cell lung cancer. Imaging-based target volume reduction in this setting is, therefore, feasible, and could potentially be considered standard of care. The procedures established might also support imaging-based target volume reduction concepts for other tumours., Funding: German Cancer Aid (Deutsche Krebshilfe)., (Copyright © 2020 Elsevier Ltd. All rights reserved.)- Published
- 2020
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18. Challenges and caveats of a multi-center retrospective radiomics study: an example of early treatment response assessment for NSCLC patients using FDG-PET/CT radiomics.
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van Timmeren JE, Carvalho S, Leijenaar RTH, Troost EGC, van Elmpt W, de Ruysscher D, Muratet JP, Denis F, Schimek-Jasch T, Nestle U, Jochems A, Woodruff HC, Oberije C, and Lambin P
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- Aged, Disease-Free Survival, Female, Humans, Male, Middle Aged, Retrospective Studies, Survival Rate, Carcinoma, Non-Small-Cell Lung diagnostic imaging, Carcinoma, Non-Small-Cell Lung mortality, Carcinoma, Non-Small-Cell Lung therapy, Databases, Factual, Fluorodeoxyglucose F18 administration & dosage, Lung Neoplasms diagnostic imaging, Lung Neoplasms mortality, Lung Neoplasms therapy, Models, Biological, Positron Emission Tomography Computed Tomography
- Abstract
Background: Prognostic models based on individual patient characteristics can improve treatment decisions and outcome in the future. In many (radiomic) studies, small size and heterogeneity of datasets is a challenge that often limits performance and potential clinical applicability of these models. The current study is example of a retrospective multi-centric study with challenges and caveats. To highlight common issues and emphasize potential pitfalls, we aimed for an extensive analysis of these multi-center pre-treatment datasets, with an additional 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) scan acquired during treatment., Methods: The dataset consisted of 138 stage II-IV non-small cell lung cancer (NSCLC) patients from four different cohorts acquired from three different institutes. The differences between the cohorts were compared in terms of clinical characteristics and using the so-called 'cohort differences model' approach. Moreover, the potential prognostic performances for overall survival of radiomic features extracted from CT or FDG-PET, or relative or absolute differences between the scans at the two time points, were assessed using the LASSO regression method. Furthermore, the performances of five different classifiers were evaluated for all image sets., Results: The individual cohorts substantially differed in terms of patient characteristics. Moreover, the cohort differences model indicated statistically significant differences between the cohorts. Neither LASSO nor any of the tested classifiers resulted in a clinical relevant prognostic model that could be validated on the available datasets., Conclusion: The results imply that the study might have been influenced by a limited sample size, heterogeneous patient characteristics, and inconsistent imaging parameters. No prognostic performance of FDG-PET or CT based radiomics models can be reported. This study highlights the necessity of extensive evaluations of cohorts and of validation datasets, especially in retrospective multi-centric datasets., Competing Interests: Author RL is CTO and shareholder of Oncoradiomics SA and co-inventor of a patent related to Radiomics. Author PL is member of the advisory board, shareholder of Oncoradiomics SA and co-inventor of two licenced & approved patents on Radiomics.
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- 2019
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19. Early Impact of Pulmonary Fractionated Stereotactic Body Radiotherapy on Quality of Life:Benefit for Patients With Low Initial Scores (STRIPE Trial).
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Adebahr S, Hechtner M, Schräder N, Schimek-Jasch T, Kaier K, Duncker-Rohr V, Gkika E, Momm F, Gaertner J, Becker G, Grosu AL, and Nestle U
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- Aged, Dose Fractionation, Radiation, Female, Follow-Up Studies, Humans, Lung Neoplasms pathology, Male, Prognosis, Prospective Studies, Surveys and Questionnaires, Health Status, Lung Neoplasms surgery, Quality of Life, Radiosurgery methods
- Abstract
Introduction: Quality of life (QoL) of comorbid patients with pulmonary malignancies is a key issue in considering fractionated stereotactic body radiotherapy (SBRT) indication. This study investigates the early impact of SBRT on QoL., Methods: One hundred patients with pulmonary lesions were treated with SBRT from February 2011 to December 2014 within the prospective, monocenter, phase II STRIPE trial. The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core module (EORTC QLQ-C30) and the QLQ-LC13 lung cancer-specific questionnaire were used to evaluate QoL before, 2 and 7 weeks after SBRT, then every 3 months for 2 years. We report on the analysis of early changes from baseline to 7-week follow-up exam. Impact of patient- and treatment-related factors on the change in QoL was analyzed., Results: QoL was assessed in 97 patients; compliance was 92% and 85% at baseline and 7 weeks after SBRT, respectively. No clinically relevant changes greater than or equal to 10 in the QoL/global health status (GHS), function scores and inquired symptoms were observed. Patients with baseline QoL below the median showed clinically relevant improvement in QoL/GHS (Δ16.7 ± 25.3, p = 0.003), emotional function (Δ14.4 ± 25.4, p = 0.013), and fatigue (Δ -10.1 ± 26.5, p = 0.089) in contrast to patients with high initial scores. No changes were observed in the dichotomized subgroups of initial Karnofsky index, Charlson Comorbidity Index, age, diagnosis, and tumor localization., Conclusions: In short-term follow-up, QoL is well maintained after pulmonary SBRT. Especially patients with low initial QoL/GHS scores show benefit from SBRT with respect to QoL., (Copyright © 2018 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.)
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- 2019
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20. Diffusion-weighted MRI and ADC versus FET-PET and GdT1w-MRI for gross tumor volume (GTV) delineation in re-irradiation of recurrent glioblastoma.
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Popp I, Bott S, Mix M, Oehlke O, Schimek-Jasch T, Nieder C, Nestle U, Bock M, Yuh WTC, Meyer PT, Weber WA, Urbach H, Mader I, and Grosu AL
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- Adult, Aged, Brain Neoplasms diagnostic imaging, Brain Neoplasms pathology, Female, Glioblastoma diagnostic imaging, Glioblastoma pathology, Humans, Magnetic Resonance Imaging methods, Male, Middle Aged, Multimodal Imaging, Prospective Studies, Tyrosine analogs & derivatives, Brain Neoplasms radiotherapy, Diffusion Magnetic Resonance Imaging methods, Glioblastoma radiotherapy, Positron-Emission Tomography methods, Radiosurgery, Re-Irradiation, Tumor Burden
- Abstract
Background and Purpose: GTV definition for re-irradiation treatment planning in recurrent glioblastoma (rGBM) is usually based on contrast-enhanced MRI (GdT1w-MRI) and, for an increased specificity, on amino acid PET. Diffusion-weighted (DWI) MRI and ADC maps can reveal regions of high cellularity as surrogate for active tumor. The objective of this study was to compare the localization and quality of diffusion restriction foci (GTV-ADClow) with FET-PET (GTV-PET) and GdT1w-MRI (GTV-GdT1w-MRI)., Material and Methods: We prospectively evaluated 41 patients, who received a fractionated stereotactic re-irradiation for rGBM. GTV-PET was generated automatically (tumor-to-background ratio 1.7-1.8) and manually customized. GTV-ADClow was manually defined based on DWI data (3D diffusion gradients, b = 0, 1000 s/mm
2 ) and parametric ADC maps. The localization of recurrence was correlated with initial GdT1w-MRI and PET data., Results: In 30/41 patients, DWI-MRI showed areas with restricted diffusion (mean ADC-value 0.74 ± 0.22 mm2 /s). 66% of GTVs-ADClow were located outside the GdT1w-MRI volume and 76% outside increased FET uptake regions. Furthermore, GTVs-ADClow were only partially included in the high dose volume and received in mean 82% of the reference dose. An adjusted volume including GdT1w-MRI, PET-positive and restricted diffusion areas would imply a GTV increase of 48%. GTV-PET and GdT1w-MRI correlated better with the localization of re-recurrence in comparison to GTV-ADClow., Conclusion: Unexpectedly, GTV-ADClow overlapped only partially with FET-PET and GdT1w-MRI in rGBM. Moreover, GTV-ADClow correlated poorly with later rGBM-recurrences. Seeing as a restricted diffusion is known to correlate with hypercellularity, this imaging discrepancy could only be further explained in histopathological studies., (Copyright © 2018 Elsevier B.V. All rights reserved.)- Published
- 2019
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21. Correction: Is serum level of CC chemokine ligand 18 a biomarker for the prediction of radiation induced lung toxicity (RILT)?
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Gkika E, Vach W, Adebahr S, Schimek-Jasch T, Brenner A, Brunner TB, Kaier K, Prasse A, Müller-Quernheim J, Grosu AL, Zissel G, and Nestle U
- Abstract
[This corrects the article DOI: 10.1371/journal.pone.0185350.].
- Published
- 2018
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22. Anatomic, functional and molecular imaging in lung cancer precision radiation therapy: treatment response assessment and radiation therapy personalization.
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MacManus M, Everitt S, Schimek-Jasch T, Li XA, Nestle U, and Kong FS
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This article reviews key imaging modalities for lung cancer patients treated with radiation therapy (RT) and considers their actual or potential contributions to critical decision-making. An international group of researchers with expertise in imaging in lung cancer patients treated with RT considered the relevant literature on modalities, including computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET). These perspectives were coordinated to summarize the current status of imaging in lung cancer and flag developments with future implications. Although there are no useful randomized trials of different imaging modalities in lung cancer, multiple prospective studies indicate that management decisions are frequently impacted by the use of complementary imaging modalities, leading both to more appropriate treatments and better outcomes. This is especially true of
18 F-fluoro-deoxyglucose (FDG)-PET/CT which is widely accepted to be the standard imaging modality for staging of lung cancer patients, for selection for potentially curative RT and for treatment planning. PET is also more accurate than CT for predicting survival after RT. PET imaging during RT is also correlated with survival and makes response-adapted therapies possible. PET tracers other than FDG have potential for imaging important biological process in tumors, including hypoxia and proliferation. MRI has superior accuracy in soft tissue imaging and the MRI Linac is a rapidly developing technology with great potential for online monitoring and modification of treatment. The role of imaging in RT-treated lung cancer patients is evolving rapidly and will allow increasing personalization of therapy according to the biology of both the tumor and dose limiting normal tissues., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare.- Published
- 2017
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23. Visualization of 4D multimodal imaging data and its applications in radiotherapy planning.
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Schlachter M, Fechter T, Adebahr S, Schimek-Jasch T, Nestle U, and Bühler K
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- Humans, Movement, Radiotherapy Dosage, Radiotherapy, Intensity-Modulated methods, Respiration, Four-Dimensional Computed Tomography methods, Lung Neoplasms diagnostic imaging, Lung Neoplasms radiotherapy, Multimodal Imaging methods, Positron-Emission Tomography methods, Radiotherapy Planning, Computer-Assisted methods
- Abstract
Purpose: To explore the benefit of using 4D multimodal visualization and interaction techniques for defined radiotherapy planning tasks over a treatment planning system used in clinical routine (C-TPS) without dedicated 4D visualization., Methods: We developed a 4D visualization system (4D-VS) with dedicated rendering and fusion of 4D multimodal imaging data based on a list of requirements developed in collaboration with radiation oncologists. We conducted a user evaluation in which the benefits of our approach were evaluated in comparison to C-TPS for three specific tasks: assessment of internal target volume (ITV) delineation, classification of tumor location in peripheral or central, and assessment of dose distribution. For all three tasks, we presented test cases for which we measured correctness, certainty, consistency followed by an additional survey regarding specific visualization features., Results: Lower quality of the test ITVs (ground truth quality was available) was more likely to be detected using 4D-VS. ITV ratings were more consistent in 4D-VS and the classification of tumor location had a higher accuracy. Overall evaluation of the survey indicates 4D-VS provides better spatial comprehensibility and simplifies the tasks which were performed during testing., Conclusions: The use of 4D-VS has improved the assessment of ITV delineations and classification of tumor location. The visualization features of 4D-VS have been identified as helpful for the assessment of dose distribution during user testing., (© 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.)
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- 2017
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24. Is serum level of CC chemokine ligand 18 a biomarker for the prediction of radiation induced lung toxicity (RILT)?
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Gkika E, Vach W, Adebahr S, Schimek-Jasch T, Brenner A, Brunner TB, Kaier K, Prasse A, Müller-Quernheim J, Grosu AL, Zissel G, and Nestle U
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- Adult, Aged, Aged, 80 and over, Biomarkers blood, Female, Humans, Lung Diseases therapy, Male, Middle Aged, Neoplasm Recurrence, Local pathology, Prognosis, Radiation Injuries blood, Chemokines, CC blood, Lung Diseases blood, Lung Diseases etiology, Radiation Injuries complications, Radiation Injuries diagnosis
- Abstract
The CC chemokine ligand 18 (CCL18) is produced by alveolar macrophages in patients with fibrosing lung disease and its concentration is increased in various fibrotic lung diseases. Furthermore CCL18 is elevated in several malignancies as it is produced by tumor associated macrophages. In this study we aimed to analyze the role of CCL18 as a prognostic biomarker for the development of early radiation induced lung toxicity (RILT), i.e. radiation pneumonitis after thoracic irradiation and its significance in the course of the disease. Sixty seven patients were enrolled prospectively in the study. Patients were treated with irradiation for several thoracic malignancies (lung cancer, esophageal cancer, thymoma), either with conventionally fractionated or hypo-fractionated radiotherapy. The CCL18 serum levels were quantified with ELISA (enzyme-linked immunosorbent assay) at predefined time points: before, during and at the end of treatment as well as in the first and second follow-up. Treatment parameters and functional tests were also correlated with the development of RILT.Fifty three patients were evaluable for this study. Twenty one patients (39%) developed radiologic signs of RILT Grade >1 but only three of them (5.6%) developed clinical symptoms (Grade 2). We could not find any association between the different CCL18 concentrations and a higher incidence of RILT. Statistical significant factors were the planning target volume (odds ratio OR: 1.003, p = 0.010), the volume of the lung receiving > 20 Gy (OR: 1.132 p = 0.004) and age (OR: 0.917, p = 0.008). There was no association between serial CCL18 concentrations with tumor response and overall survival.In our study the dosimetric parameters remained the most potent predictors of RILT. Further studies are needed in order to estimate the role of CCL18 in the development of early RILT.
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- 2017
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25. Stereotactic body radiotherapy (SBRT) in recurrent or oligometastatic pancreatic cancer : A toxicity review of simultaneous integrated protection (SIP) versus conventional SBRT.
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Gkika E, Adebahr S, Kirste S, Schimek-Jasch T, Wiehle R, Claus R, Wittel U, Nestle U, Baltas D, Grosu AL, and Brunner TB
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- Adenocarcinoma mortality, Adenocarcinoma pathology, Adult, Aged, Cohort Studies, Combined Modality Therapy, Disease Progression, Female, Humans, Magnetic Resonance Imaging, Male, Middle Aged, Neoplasm Metastasis, Neoplasm Recurrence, Local mortality, Neoplasm Recurrence, Local surgery, Neoplasm Staging, Organs at Risk radiation effects, Pancreatic Neoplasms mortality, Pancreatic Neoplasms pathology, Pancreatic Neoplasms surgery, Positron Emission Tomography Computed Tomography, Radiotherapy Dosage, Radiotherapy Planning, Computer-Assisted, Radiotherapy, Adjuvant methods, Retrospective Studies, Survival Analysis, Tomography, X-Ray Computed, Adenocarcinoma radiotherapy, Neoplasm Recurrence, Local radiotherapy, Pancreatic Neoplasms radiotherapy, Radiation Protection methods, Radiosurgery methods, Radiotherapy, Intensity-Modulated methods
- Abstract
Background: Stereotactic body radiotherapy (SBRT) in pancreatic cancer can be limited by its proximity to organs at risk (OAR). In this analysis, we evaluated the toxicity and efficacy of two different treatment approaches in patients with locally recurrent or oligometastatic pancreatic cancer., Materials and Methods: According to the prescription method, patients were divided in two cohorts (C1 and C2). The planning target volume (PTV) was created through a 4 mm expansion of the internal target volume. In C2, a subvolume was additionally created, a simultaneous integrated protection (SIP), which is the overlap of the PTV with the planning risk volume of an OAR to which we prescribed a reduced dose., Results: In all, 18 patients were treated (7 with local recurrences, 9 for oligometastases, 2 for both). Twelve of 23 lesions were treated without SIP (C1) and 11 with SIP (C2). The median follow-up was 12.8 months. Median overall survival (OS) was 13.2 (95% confidence interval [CI] 9.8-14.6) months. The OS rates at 6 and 12 months were 87 and 58%, respectively. Freedom from local progression for combined cohorts at 6 and 12 months was 93 and 67% (95% CI 15-36), respectively. Local control was not statistically different between the two groups. One patient in C2 experienced grade ≥3 acute toxicities and 1 patient in C1 experienced a grade ≥3 late toxicity., Conclusion: The SIP approach is a useful prescription method for abdominal SBRT with a favorable toxicity profile which does not compromise local control and overall survival despite dose sacrifices in small subvolumes.
- Published
- 2017
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26. Using a contextualized sensemaking model for interaction design: A case study of tumor contouring.
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Aselmaa A, van Herk M, Laprie A, Nestle U, Götz I, Wiedenmann N, Schimek-Jasch T, Picaud F, Syrykh C, Cagetti LV, Jolnerovski M, Song Y, and Goossens RH
- Subjects
- Comprehension, Female, Humans, Male, Models, Theoretical, Cognition, Health Information Systems, Neoplasms, Software
- Abstract
Sensemaking theories help designers understand the cognitive processes of a user when he/she performs a complicated task. This paper introduces a two-step approach of incorporating sensemaking support within the design of health information systems by: (1) modeling the sensemaking process of physicians while performing a task, and (2) identifying software interaction design requirements that support sensemaking based on this model. The two-step approach is presented based on a case study of the tumor contouring clinical task for radiotherapy planning. In the first step of the approach, a contextualized sensemaking model was developed to describe the sensemaking process based on the goal, the workflow and the context of the task. In the second step, based on a research software prototype, an experiment was conducted where three contouring tasks were performed by eight physicians respectively. Four types of navigation interactions and five types of interaction sequence patterns were identified by analyzing the gathered interaction log data from those twenty-four cases. Further in-depth study on each of the navigation interactions and interaction sequence patterns in relation to the contextualized sensemaking model revealed five main areas for design improvements to increase sensemaking support. Outcomes of the case study indicate that the proposed two-step approach was beneficial for gaining a deeper understanding of the sensemaking process during the task, as well as for identifying design requirements for better sensemaking support., (Copyright © 2016. Published by Elsevier Inc.)
- Published
- 2017
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27. Amino-acid PET versus MRI guided re-irradiation in patients with recurrent glioblastoma multiforme (GLIAA) - protocol of a randomized phase II trial (NOA 10/ARO 2013-1).
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Oehlke O, Mix M, Graf E, Schimek-Jasch T, Nestle U, Götz I, Schneider-Fuchs S, Weyerbrock A, Mader I, Baumert BG, Short SC, Meyer PT, Weber WA, and Grosu AL
- Subjects
- Brain Neoplasms diagnostic imaging, Disease-Free Survival, Female, Glioblastoma diagnostic imaging, Humans, Male, Neoplasm Recurrence, Local diagnostic imaging, Prospective Studies, Quality of Life, Radiotherapy Planning, Computer-Assisted, Re-Irradiation, Survival Analysis, Treatment Outcome, Brain Neoplasms radiotherapy, Diffusion Magnetic Resonance Imaging methods, Glioblastoma radiotherapy, Neoplasm Recurrence, Local radiotherapy, Positron-Emission Tomography methods
- Abstract
Background: The higher specificity of amino-acid positron emission tomography (AA-PET) in the diagnosis of gliomas, as well as in the differentiation between recurrence and treatment-related alterations, in comparison to contrast enhancement in T1-weighted MRI was demonstrated in many studies and is the rationale for their implementation into radiation oncology treatment planning. Several clinical trials have demonstrated the significant differences between AA-PET and standard MRI concerning the definition of the gross tumor volume (GTV). A small single-center non-randomized prospective study in patients with recurrent high grade gliomas treated with stereotactic fractionated radiotherapy (SFRT) showed a significant improvement in survival when AA-PET was integrated in target volume delineation, in comparison to patients treated based on CT/MRI alone., Methods: This protocol describes a prospective, open label, randomized, multi-center phase II trial designed to test if radiotherapy target volume delineation based on FET-PET leads to improvement in progression free survival (PFS) in patients with recurrent glioblastoma (GBM) treated with re-irradiation, compared to target volume delineation based on T1Gd-MRI. The target sample size is 200 randomized patients with a 1:1 allocation ratio to both arms. The primary endpoint (PFS) is determined by serial MRI scans, supplemented by AA-PET-scans and/or biopsy/surgery if suspicious of progression. Secondary endpoints include overall survival (OS), locally controlled survival (time to local progression or death), volumetric assessment of GTV delineated by either method, topography of progression in relation to MRI- or PET-derived target volumes, rate of long term survivors (>1 year), localization of necrosis after re-irradiation, quality of life (QoL) assessed by the EORTC QLQ-C15 PAL questionnaire, evaluation of safety of FET-application in AA-PET imaging and toxicity of re-irradiation., Discussion: This is a protocol of a randomized phase II trial designed to test a new strategy of radiotherapy target volume delineation for improving the outcome of patients with recurrent GBM. Moreover, the trial will help to develop a standardized methodology for the integration of AA-PET and other imaging biomarkers in radiation treatment planning., Trial Registration: The GLIAA trial is registered with ClinicalTrials.gov ( NCT01252459 , registration date 02.12.2010), German Clinical Trials Registry ( DRKS00000634 , registration date 10.10.2014), and European Clinical Trials Database (EudraCT-No. 2012-001121-27, registration date 27.02.2012).
- Published
- 2016
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28. Visualization of Deformable Image Registration Quality Using Local Image Dissimilarity.
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Schlachter M, Fechter T, Jurisic M, Schimek-Jasch T, Oehlke O, Adebahr S, Birkfellner W, Nestle U, and Buhler K
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- Algorithms, Humans, Lung diagnostic imaging, Lung Neoplasms diagnostic imaging, Radiography, Thoracic, Radiotherapy, Image-Guided, Reproducibility of Results, Tomography, X-Ray Computed, Image Processing, Computer-Assisted methods
- Abstract
Deformable image registration (DIR) has the potential to improve modern radiotherapy in many aspects, including volume definition, treatment planning and image-guided adaptive radiotherapy. Studies have shown its possible clinical benefits. However, measuring DIR accuracy is difficult without known ground truth, but necessary before integration in the radiotherapy workflow. Visual assessment is an important step towards clinical acceptance. We propose a visualization framework which supports the exploration and the assessment of DIR accuracy. It offers different interaction and visualization features for exploration of candidate regions to simplify the process of visual assessment. The visualization is based on voxel-wise comparison of local image patches for which dissimilarity measures are computed and visualized to indicate locally the registration results. We performed an evaluation with three radiation oncologists to demonstrate the viability of our approach. In the evaluation, lung regions were rated by the participants with regards to their visual accuracy and compared to the registration error measured with expert defined landmarks. Regions rated as "accepted" had an average registration error of 1.8 mm, with the highest single landmark error being 3.3 mm. Additionally, survey results show that the proposed visualizations support a fast and intuitive investigation of DIR accuracy, and are suitable for finding even small errors.
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- 2016
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29. Oesophagus side effects related to the treatment of oesophageal cancer or radiotherapy of other thoracic malignancies.
- Author
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Adebahr S, Schimek-Jasch T, Nestle U, and Brunner TB
- Subjects
- Humans, Esophageal Neoplasms radiotherapy, Esophagitis etiology, Esophagus radiation effects, Thoracic Neoplasms radiotherapy
- Abstract
The oesophagus as a serial organ located in the central chest is frequent subject to "incidental" dose application in radiotherapy for several thoracic malignancies including oesophageal cancer itself. Especially due to the radiosensitive mucosa severe radiotherapy induced sequelae can occur, acute oesophagitis and strictures as late toxicity being the most frequent side-effects. In this review we focus on oesophageal side effects derived from treatment of gastrointestinal cancer and secondly provide an overview on oesophageal toxicity from conventional and stereotactic fractionated radiotherapy to the thoracic area in general. Available data on pathogenesis, frequency, onset, and severity of oesophageal side effects are summarized. Whereas for conventional radiotherapy the associations of applied doses to certain volumes of the oesophagus are well described, the tolerance dose to the mediastinal structures for hypofractionated therapy is unknown. The review provides available attempts to predict the risk of oesophageal side effects from dosimetric parameters of SBRT., (Copyright © 2016 Elsevier Ltd. All rights reserved.)
- Published
- 2016
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30. User Interaction in Semi-Automatic Segmentation of Organs at Risk: a Case Study in Radiotherapy.
- Author
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Ramkumar A, Dolz J, Kirisli HA, Adebahr S, Schimek-Jasch T, Nestle U, Massoptier L, Varga E, Stappers PJ, Niessen WJ, and Song Y
- Subjects
- Algorithms, Humans, Observer Variation, Reproducibility of Results, Imaging, Three-Dimensional, Organs at Risk diagnostic imaging, Pattern Recognition, Automated, Radiotherapy
- Abstract
Accurate segmentation of organs at risk is an important step in radiotherapy planning. Manual segmentation being a tedious procedure and prone to inter- and intra-observer variability, there is a growing interest in automated segmentation methods. However, automatic methods frequently fail to provide satisfactory result, and post-processing corrections are often needed. Semi-automatic segmentation methods are designed to overcome these problems by combining physicians' expertise and computers' potential. This study evaluates two semi-automatic segmentation methods with different types of user interactions, named the "strokes" and the "contour", to provide insights into the role and impact of human-computer interaction. Two physicians participated in the experiment. In total, 42 case studies were carried out on five different types of organs at risk. For each case study, both the human-computer interaction process and quality of the segmentation results were measured subjectively and objectively. Furthermore, different measures of the process and the results were correlated. A total of 36 quantifiable and ten non-quantifiable correlations were identified for each type of interaction. Among those pairs of measures, 20 of the contour method and 22 of the strokes method were strongly or moderately correlated, either directly or inversely. Based on those correlated measures, it is concluded that: (1) in the design of semi-automatic segmentation methods, user interactions need to be less cognitively challenging; (2) based on the observed workflows and preferences of physicians, there is a need for flexibility in the interface design; (3) the correlated measures provide insights that can be used in improving user interaction design.
- Published
- 2016
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31. Improved inter-observer agreement of an expert review panel in an oncology treatment trial--Insights from a structured interventional process.
- Author
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Nestle U, Rischke HC, Eschmann SM, Holl G, Tosch M, Miederer M, Plotkin M, Essler M, Puskas C, Schimek-Jasch T, Duncker-Rohr V, Rühl F, Leifert A, Mix M, Grosu AL, König J, and Vach W
- Subjects
- Carcinoma, Non-Small-Cell Lung therapy, Chemoradiotherapy methods, Double-Blind Method, Fluorodeoxyglucose F18, Humans, Lung Neoplasms therapy, Observer Variation, Outcome Assessment, Health Care methods, Reproducibility of Results, Sensitivity and Specificity, Carcinoma, Non-Small-Cell Lung diagnosis, Lung Neoplasms diagnosis, Positron-Emission Tomography methods, Tomography, X-Ray Computed methods
- Abstract
Purpose: Oncologic imaging is a key for successful cancer treatment. While the quality assurance (QA) of image acquisition protocols has already been focussed, QA of reading and reporting offers still room for improvement. The latter was addressed in the context of a prospective multicentre trial on fluoro-deoxyglucose (FDG)-positron-emission tomography (PET)/CT-based chemoradiotherapy for locally advanced non-small cell lung cancer (NSCLC)., Material and Methods: An expert panel was prospectively installed performing blinded reviews of mediastinal NSCLC involvement in FDG-PET/CT. Due to a high initial reporting inter-observer disagreement, the independent data monitoring committee (IDMC) triggered an interventional harmonisation process, which overall involved 11 experts uttering 6855 blinded diagnostic statements. After assessing the baseline inter-observer agreement (IOA) of a blinded re-review (phase 1), a discussion process led to improved reading criteria (phase 2). Those underwent a validation study (phase 3) and were then implemented into the study routine. After 2 months (phase 4) and 1 year (phase 5), the IOA was reassessed., Results: The initial overall IOA was moderate (kappa 0.52 CT; 0.53 PET). After improvement of reading criteria, the kappa values improved substantially (kappa 0.61 CT; 0.66 PET), which was retained until the late reassessment (kappa 0.71 CT; 0.67 PET). Subjective uncertainty was highly predictive for low IOA., Conclusion: The IOA of an expert panel was significantly improved by a structured interventional harmonisation process which could be a model for future clinical trials. Furthermore, the low IOA in reporting nodal involvement in NSCLC may bear consequences for individual patient care., (Copyright © 2015 Elsevier Ltd. All rights reserved.)
- Published
- 2015
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32. A teaching intervention in a contouring dummy run improved target volume delineation in locally advanced non-small cell lung cancer: Reducing the interobserver variability in multicentre clinical studies.
- Author
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Schimek-Jasch T, Troost EG, Rücker G, Prokic V, Avlar M, Duncker-Rohr V, Mix M, Doll C, Grosu AL, and Nestle U
- Subjects
- Carcinoma, Non-Small-Cell Lung diagnostic imaging, Clinical Competence, Germany, Humans, Lung Neoplasms diagnostic imaging, Netherlands, Observer Variation, Radionuclide Imaging, Radiotherapy Dosage, Reproducibility of Results, Sensitivity and Specificity, Tumor Burden, Carcinoma, Non-Small-Cell Lung pathology, Carcinoma, Non-Small-Cell Lung radiotherapy, Lung Neoplasms pathology, Lung Neoplasms radiotherapy, Manikins, Radiation Oncology education, Radiotherapy Planning, Computer-Assisted methods
- Abstract
Introduction: Interobserver variability in the definition of target volumes (TVs) is a well-known confounding factor in (multicentre) clinical studies employing radiotherapy. Therefore, detailed contouring guidelines are provided in the prospective randomised multicentre PET-Plan (NCT00697333) clinical trial protocol. This trial compares strictly FDG-PET-based TV delineation with conventional TV delineation in patients with locally advanced non-small cell lung cancer (NSCLC). Despite detailed contouring guidelines, their interpretation by different radiation oncologists can vary considerably, leading to undesirable discrepancies in TV delineation. Considering this, as part of the PET-Plan study quality assurance (QA), a contouring dummy run (DR) consisting of two phases was performed to analyse the interobserver variability before and after teaching., Materials and Methods: In the first phase of the DR (DR1), radiation oncologists from 14 study centres were asked to delineate TVs as defined by the study protocol (gross TV, GTV; and two clinical TVs, CTV-A and CTV-B) in a test patient. A teaching session was held at a study group meeting, including a discussion of the results focussing on discordances in comparison to the per-protocol solution. Subsequently, the second phase of the DR (DR2) was performed in order to evaluate the impact of teaching., Results: Teaching after DR1 resulted in a reduction of absolute TVs in DR2, as well as in better concordance of TVs. The Overall Kappa(κ) indices increased from 0.63 to 0.71 (GTV), 0.60 to 0.65 (CTV-A) and from 0.59 to 0.63 (CTV-B), demonstrating improvements in overall interobserver agreement., Conclusion: Contouring DRs and study group meetings as part of QA in multicentre clinical trials help to identify misinterpretations of per-protocol TV delineation. Teaching the correct interpretation of protocol contouring guidelines leads to a reduction in interobserver variability and to more consistent contouring, which should consequently improve the validity of the overall study results.
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- 2015
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33. Impact of 4D-(18)FDG-PET/CT imaging on target volume delineation in SBRT patients with central versus peripheral lung tumors. Multi-reader comparative study.
- Author
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Chirindel A, Adebahr S, Schuster D, Schimek-Jasch T, Schanne DH, Nemer U, Mix M, Meyer P, Grosu AL, Brunner T, and Nestle U
- Subjects
- Aged, Aged, 80 and over, Cone-Beam Computed Tomography, Female, Humans, Lung Neoplasms pathology, Male, Middle Aged, Multimodal Imaging, Positron-Emission Tomography methods, Lung Neoplasms diagnostic imaging
- Abstract
Purpose: Evaluation of the effect of co-registered 4D-(18)FDG-PET/CT for SBRT target delineation in patients with central versus peripheral lung tumors., Methods: Analysis of internal target volume (ITV) delineation of central and peripheral lung lesions in 21 SBRT-patients. Manual delineation was performed by 4 observers in 2 contouring phases: on respiratory gated 4DCT with diagnostic 3DPET available aside (CT-ITV) and on co-registered 4DPET/CT (PET/CT-ITV). Comparative analysis of volumes and inter-reader agreement., Results: 11 cases of peripheral and 10 central lesions were evaluated. In peripheral lesions, average CT-ITV was 6.2 cm(3) and PET/CT-ITV 8.6 cm(3), resembling a mean change in hypothetical radius of 2 mm. For both CT-ITVs and PET/CT-ITVs inter reader agreement was good and unchanged (0.733 and 0.716; p=0.58). All PET/CT-ITVs stayed within the PTVs derived from CT-ITVs. In central lesions, average CT-ITVs were 42.1 cm(3), PET/CT-ITVs 44.2 cm(3), without significant overall volume changes. Inter-reader agreement improved significantly (0.665 and 0.750; p<0.05). 2/10 PET/CT-ITVs exceeded the PTVs derived from CT-ITVs by >1 ml in average for all observers., Conclusion: The addition of co-registered 4DPET data to 4DCT based target volume delineation for SBRT of centrally located lung tumors increases the inter-observer agreement and may help to avoid geographic misses., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2015
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34. Measuring inter-observer agreement in contour delineation of medical imaging in a dummy run using Fleiss' kappa.
- Author
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Rücker G, Schimek-Jasch T, and Nestle U
- Subjects
- Algorithms, Humans, Multicenter Studies as Topic, Neoplasms radiotherapy, Prospective Studies, Radiotherapy Planning, Computer-Assisted statistics & numerical data, Randomized Controlled Trials as Topic, Form Perception, Observer Variation, Radiotherapy Planning, Computer-Assisted methods
- Abstract
Background: In medical imaging used for planning of radiation therapy, observers delineate contours of a treatment volume in a series of images of uniform slice thickness., Objective: To summarize agreement in contouring between an arbitrary number of observers by a single number, we generalized the kappa index proposed by Zijdenbos et al. (1994)., Methods: Observers characterized voxels by allocating them to one of two categories, inside or outside the contoured region. Fleiss' kappa was used to measure association between n indistinguishable observers. Given the number Vi of voxels contoured by exactly i observers (i = 1, ..., n ), the resulting overall kappa is representable as a ratio of weighted sums of the Vi ., Results: Overall kappa was applied to analyze inter-center variations in a multicenter trial on radiotherapy planning in patients with locally advanced lung cancer. A contouring dummy run was performed within the quality assurance program. Contouring was done twice, once before and once after a training program. Observer agreement was enhanced from 0.59 (with a 95% confidence interval (CI) of 0.51-0.67) to 0.69 (95% CI 0.59-0.78)., Conclusion: By contrast to average pairwise indices, overall kappa measures observer agreement for more than two observers using the full information about overlapping volumes, while not distinguishing between observers. It is particularly adequate for measuring observer agreement when identification of observers is not possible or desirable and when there is no gold standard.
- Published
- 2012
- Full Text
- View/download PDF
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