Search

Abstract Background To define a suitable threshold setting for gross tumor volume (GTV) when using 18Fluoro-deoxyglucose positron emission tomography and computed tomogram (PET/CT) for radiotherapy planning in head and neck cancer (HNC). Methods Fifteen HNC patients prospectively received PET/CT simulation for their radiation treatment planning. Biological target volume (BTV) was derived from PET/CT-based GTV of the primary tumor. The BTVs were defined as the isodensity volumes when adjusting different percentage of the maximal standardized uptake value (SUVmax), excluding any artifact from surrounding normal tissues. CT-based primary GTV (C-pGTV) that had been previously defined by radiation oncologists was compared with the BTV. Suitable threshold level (sTL) could be determined when BTV value and its morphology using a certain threshold level was observed to be the best fitness of the C-pGTV. Suitable standardized uptake value (sSUV) was calculated as the sTL multiplied by the SUVmax. Results Our result demonstrated no single sTL or sSUV method could achieve an optimized volumetric match with the C-pGTV. The sTL was 13% to 27% (mean, 19%), whereas the sSUV was 1.64 to 3.98 (mean, 2.46). The sTL was inversely correlated with the SUVmax [sTL = -0.1004 Ln (SUVmax) + 0.4464; R2 = 0.81]. The sSUV showed a linear correlation with the SUVmax (sSUV = 0.0842 SUVmax + 1.248; R2 = 0.89). The sTL was not associated with the value of C-pGTVs. Conclusion In PET/CT-based BTV for HNC, a suitable threshold or SUV level can be established by correlating with SUVmax rather than using a fixed threshold.

Hepatocellular carcinoma (HCC) is a disease usually diagnosed in its advanced-stage, and is frequently not amenable to curative surgical treatment. Also, HCC is resistant to chemotherapy and less vulnerable to radiation therapy compared to normal hepatic parenchyma. Both of these facts render the efficacy of adjuvant and palliative treatments problematic. Selective internal radiation therapy (SIRT) with Y-bearing microspheres is characterized by preferentially delivering substantially high doses of radiation to a liver tumor dose simultaneously limiting the damage to its non-tumorous cells, providing an opportunity for effective local tumor control and even tumor regression therapy. The current article reviews the specific characters, dosimetry, possible applications, and special considerations toward the pre-existing radiation therapy of Y microsphere SIRT in treating HCC. [ABSTRACT FROM AUTHOR]

Background: Neoadjuvant chemoradiotherapy (NCRT) followed by surgery is the standard treatment for patients with locally advanced rectal cancer. This study developed a random forest (RF) model to predict pathological complete response (pCR) based on radiomics derived from baseline 18 F-fluorodeoxyglucose ([ 18 F]FDG)-positron emission tomography (PET)/computed tomography (CT)., Methods: This study included 169 patients with newly diagnosed rectal cancer. All patients received 18 F[FDG]-PET/CT, NCRT, and surgery. In total, 68 radiomic features were extracted from the metabolic tumor volume. The numbers of splits in a decision tree and trees in an RF were determined based on their effects on predictive performance. Receiver operating characteristic curve analysis was performed to evaluate predictive performance and ascertain the optimal threshold for maximizing prediction accuracy., Results: After NCRT, 22 patients (13%) achieved pCR, and 42 features that could differentiate tumors with pCR were used to construct the RF model. Six decision trees and seven splits were suitable. Accordingly, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 81.8%, 97.3%, 81.8%, 97.3%, and 95.3%, respectively., Conclusions: By using an RF, we determined that radiomics derived from baseline 18 F[FDG]-PET/CT could accurately predict pCR in patients with rectal cancer. Highly accurate and predictive values can be achieved but should be externally validated., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare., (2020 Annals of Translational Medicine. All rights reserved.)

To know tumor PD-L1 expression through IHC or the FDG-PET related radiomics, we investigated the association between programmed cell death protein 1 ligand (PD-L1) expression and immunohistochemical (IHC) biomarkers or textural features of 18F-fluoro-2-deoxdeoxyglucose positron emission tomography ( 18 F-FDG PET) in 53 oropharyngeal or hypopharyngeal cancer patients who were ready to undergo radiotherapy-based treatment. Differences in textural features or biomarkers between tumors with and without PD-L1 expression were tested using a Mann-Whitney U test. The predicted values for PD-L1 expression were examined using logistic regression analysis. The mean percentages of tumor PD-L1 expression were 6.2 ± 13.5. Eighteen tumors had PD-L1 expression ≥5%, whereas 30 tumors ≥1%. Using a 5% cutoff, the p16 staining percentage and the textural index of correlation were two factors associated with PD-L1 expression. The odds ratios (ORs) were 17.00 (p = 0.028) and 0.009 (p = 0.015), respectively. When dichotomizing PD-L1 at 1%, the p16 and Ki-67 staining percentages were two predictors for PD-L1 expression with ORs of 11.41 (p = 0.035) and 757.77 (p = 0.045). p16 and Ki-67 staining percentages and several PET/CT-derived textural features can provide supplemental information to determine tumor PD-L1 expression in HNCs.

Background: This study aimed to determine the relationship between the pre-operative metabolic tumor volume (MTV) and the disease-free survival (DFS) of patients with stage I non-small cell lung cancer (NSCLC) using F-18 2-fluoro-2-deoxy-D-glucose (FDG) positron-emission tomography-computed tomography (PET-CT) scanning., Materials and Methods: Data from sixty patients with stage I NSCLC who had undergone preoperative F-18 FDG PET-CT scanning were retrospectively analyzed. The early and late maximum standardized uptake values (eSUVm and lSUVm, respectively) were measured from attenuation-corrected F-18 FDG PET-CT images. Three MTV segmentation methods were applied as an isocontour at an early SUV of 2.5 (MTV2.5) or using fixed thresholds of either 40% (MTV40%) or 50% (MTV50%) of the maximum intratumoral F-18 FDG activity. DFS was compared by employing the Kaplan-Meier method, using the median values as cutoffs for each parameter. The log-rank test and Cox regression were performed to explore the effect of the different MTV variables on DFS. Time-dependent receiver operating characteristic (ROC) curves were created to evaluate the predictive performance., Results: During a median follow-up duration of 24 months, two patients died of disease progression, and 11 experienced recurrent tumors (eight intrathoracic tumors, two distant metastasis, and one both types of recurrences). The univariate analyses showed that pathological stage 1B, histological type of squamous cell carcinoma, male sex, maximum tumor size over 2 cm, eSUVm, lSUVm, and MTV2.5 were associated with reduced DFS. Patients who had tumors with large eSUVm or large lSUVm had a significantly lower 2-year DFS, compared with patients who had smaller tumors (65% vs. 96%, p=0.002; 63% vs. 96%, p=0.000). Patients with an MTV2.5 greater than 9.8 ml had a lower 2-year DFS than those with an MTV of 9.8 ml or greater (59 vs. 85%, p=0.02). However, multivariate analysis showed that lSUVm over 3.4 was the only parameter that exhibited an impact on DFS (p=0.05, hazard ratio=10.7), and the observed influence was marginal., Conclusion: For patients with stage I NSCLC treated with surgery, preoperative MTV parameters have a limited prognostic value for predicting DFS.

Aim: To investigate the prognostic role of the pretreatment metabolic tumor volume (MTV) as determined by Positron emission tomography--computed tomography (PET-CT) in patients with esophageal cancer undergoing curative surgery., Patients and Methods: We retrospectively reviewed the data of 26 patients with squamous cell carcinoma of the esophagus, who underwent 18F-Fluorodeoxyglucose PET-CT before surgery. MTVs were defined as the volumes with FDG uptake above a standardized uptake value (SUV) of 2.5 (MTV2.5), or a fixed threshold of 20% (MTV20%) of the maximum intratumoral activity. Overall survival (OS) and disease-free survival (DFS) were examined by the Kaplan-Meier method and the log-rank test., Results: In a median follow-up of 15 months, 13 patients had died. The mean MTV2.5 was 18.9 ± 15.4 ml (median, 16.0), whereas the mean MTV20% was 21.7 ± 15.0 ml (median, 19.1). Patients who had tumors of an MTV2.5 >16.0 ml had an inferior one-year OS compared with patients with a lower MTV2.5 (70% vs. 84%, p=0.018). Similarly, patients with an MTV20% >19.1 ml had poorer outcomes compared with patients who had small tumors, with one-year OS of 69% and 85%, respectively (p=0.016). No statistical significance was found in DFS for both MTV approaches. The SUVp-max had no impact on the OS and the DFS when using a median value of 8.3., Conclusion: Pretreatment MTV is a novel marker for OS of patients with esophageal cancer treated with curative surgery. For those with higher MTVs, more aggressive adjuvant treatments should be considered.

A combination of four-dimensional computed tomography with (18)F-fluorodeoxyglucose positron emission tomography (4D CT-FDG PET) was used to delineate gross tumor volume (GTV) in esophageal cancer (EC). Eighteen patients with EC were prospectively enrolled. Using 4D images taken during the respiratory cycle, the average CT image phase was fused with the average FDG PET phase in order to analyze the optimal standardized uptake values (SUV) or threshold. PET-based GTV (GTV(PET)) was determined with eight different threshold methods using the auto-contouring function on the PET workstation. The difference in volume ratio (VR) and conformality index (CI) between GTV(PET) and CT-based GTV (GTV(CT)) was investigated. The image sets via automatic co-registrations of 4D CT-FDG PET were available for 12 patients with 13 GTV(CT) values. The decision coefficient (R(2)) of tumor length difference at the threshold levels of SUV 2.5, SUV 20% and SUV 25% were 0.79, 0.65 and 0.54, respectively. The mean volume of GTV(CT) was 29.41 ± 19.14 ml. The mean VR ranged from 0.30 to 1.48. The optimal VR of 0.98, close to 1, was at SUV 20% or SUV 2.5. The mean CI ranged from 0.28 to 0.58. The best CI was at SUV 20% (0.58) or SUV 2.5 (0.57). The auto-contouring function of the SUV threshold has the potential to assist in contouring the GTV. The SUV threshold setting of SUV 20% or SUV 2.5 achieves the optimal correlation of tumor length, VR, and CI using 4D-PET/CT images.