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Purpose: Combination of immune checkpoint inhibitors with chemotherapy is under investigation for cancer treatment., Experimental Design: We studied the rationale of such a combination for treating mesothelioma, a disease with limited treatment options., Results: The combination of gemcitabine and immune checkpoint inhibitors outperformed immunotherapy alone with regard to tumor control and survival in a preclinical mesothelioma model; however, the addition of dexamethasone to gemcitabine and immune checkpoint inhibitors nullified the synergistic clinical response. Furthermore, treatment with gemcitabine plus anti-PD-1 resulted in an objective clinical response in two patients with mesothelioma, who were resistant to gemcitabine or anti-PD-1 as monotherapy., Conclusions: Thus, treatment of mesothelioma with a combination of gemcitabine with immune checkpoint inhibitors is feasible and results in synergistic clinical response compared with single treatment in the absence of steroids., (©2018 American Association for Cancer Research.)

Background: Radiomics is a promising methodology for quantitative analysis and description of radiological images using advanced mathematics and statistics. Tumor delineation, which is still often done manually, is an essential step in radiomics, however, inter-observer variability is a well-known uncertainty in radiation oncology. This study investigated the impact of inter-observer variability (IOV) in manual tumor delineation on the reliability of radiomic features (RF)., Methods: Three different tumor types (head and neck squamous cell carcinoma (HNSCC), malignant pleural mesothelioma (MPM) and non-small cell lung cancer (NSCLC)) were included. For each site, eleven individual tumors were contoured on CT scans by three experienced radiation oncologists. Dice coefficients (DC) were calculated for quantification of delineation variability. RF were calculated with an in-house developed software implementation, which comprises 1404 features: shape (n = 18), histogram (n = 17), texture (n = 137) and wavelet (n = 1232). The IOV of RF was studied using the intraclass correlation coefficient (ICC). An ICC >0.8 indicates a good reproducibility. For the stable RF, an average linkage hierarchical clustering was performed to identify classes of uncorrelated features., Results: Median DC was high for NSCLC (0.86, range 0.57-0.90) and HNSCC (0.72, 0.21-0.89), whereas it was low for MPM (0.26, 0-0.9) indicating substantial IOV. Stability rate of RF correlated with DC and depended on tumor site, showing a high stability in NSCLC (90% of total parameters), acceptable stability in HNSCC (59% of total parameters) and low stability in MPM (36% of total parameters). Shape features showed the weakest stability across all tumor types. Hierarchical clustering revealed 14 groups of correlated and stable features for NSCLC and 6 groups for both HNSCC and MPM., Conclusion: Inter-observer delineation variability has a relevant influence on radiomics analysis and is strongly influenced by tumor type. This leads to a reduced number of suitable imaging features.

Introduction: Alterations of the tumor suppressor Neurofibromatosis type II (NF2) have been reported in about 40% of Malignant pleural mesothelioma (MPM) patients. NF2 (Merlin) deficiency leads to alterations of the Hippo pathway; resulting in activation of the oncogenic Yes Associated Protein-1 (YAP1). Our aim was to investigate the association between these alterations and clinical outcomes., Material and Methods: Tissue microarrays composed of MPM tumors derived from 2 independent MPM cohorts were employed for this study. Immunohistochemical expression of Merlin, YAP1 and its target genes, Survivin and connective tissue growth factor (CTGF) were assessed in nuclear and cytoplasmic fractions. Cohort 1 was comprised of 145 patients intended to be treated with chemotherapy (CTX) followed by extrapleural pneumonectomy (EPP), thus both pre- and post-CTX tissues were available. Cohort 2 was comprised of 59 patients treated with EPP followed by intraoperative hyperthermic cisplatin and/or adjuvant CTX and/or radiotherapy. Marker expression was quantified by means of labeling index (%) for nuclear Survivin and by H-score for the other markers. The dichotomized marker expression was tested for the association with overall survival (OS) and freedom from recurrence (FFR)., Results: Kaplan-Meier survival curves revealed a significant association between low cytoplasmic Merlin expression in pre-induction CTX tissues of cohort 1 with shorter FFR (p = 0.02) and OS (p = 0.03). The same tendency was observed in the chemotherapy naïve tissues obtained during EPP of cohort 2. Low nuclear Merlin expression in post-CTX tissues (available from cohort 1 only) was associated with shorter FFR (p = 0.04) and OS (p = 0.05). High nuclear Survivin labeling indices in both pre- and post-CTX tissues of cohort 1 was associated with shorter FFR (p = 0.02). In cohort 2, this was associated with both FFR and OS (p = 0.046 and p = 0.002, respectively). In multivariate analysis, low expression of cytoplasmic Merlin remained an independent prognosticator for shorter FFR of cohort 1 [hazard ratio (HR) = 0.5, 95% confidence interval (CI) = 0.3-0.9, p = 0.001] and OS [HR = 0.5, 95% CI = 0.3-1, p = 0.04]. High Survivin labeling index was an independent prognostic factor for shorter FFR in patients from cohort 1 [HR = 3.4, 95% CI = 1.7-6.8, p = 0.006] and shorter OS in patients from cohort 2 [HR = 2.35, 95% CI = 1.27-4.33, p = 0.006]., Conclusions: Our findings uncover the significance of Merlin protein expression and Survivin labeling index as prognosticators for poor clinical outcome in two independent MPM cohorts. If confirmed, these markers may be used to identify subgroups of patients benefitting from additional treatment., (Copyright © 2016 Federation of European Biochemical Societies. All rights reserved.)

Objectives: To analyse the relapse pattern and influence of second-line treatment after recurrence of malignant pleural mesothelioma (MPM) in patients who had previously undergone multimodality treatment., Methods: Between September 1999 and December 2013, 136 patients underwent macroscopic complete resection (MCR) by extrapleural pneumonectomy after induction chemotherapy for MPM. We analysed 106 patients who presented with recurrent disease until October 2014. Data were retrieved from our mesothelioma database, with additional information regarding precise localization gathered by reviewing the imaging and medical records., Results: The overall recurrence rate was 78% (106/136 patients). The median freedom from recurrence was 9 months after surgery [95% confidence interval (95% CI) 7-10]. Local recurrence only was observed in 33 patients (31%), distant metastases only in 27 patients (26%) and simultaneous distant and local recurrence in 46 patients (43%). Local recurrence was observed significantly less frequently in patients having received adjuvant radiotherapy (19 vs 47%, P = 0.003), but there was no significant impact on overall survival (OS) [radiation: 22 months (95% CI 19-24); no-radiation: 23 months (95% CI 18-27), P = 0.6]. The median OS was 22 months (95% CI 21-24), median post-recurrence survival (PRS) was 7 months (95% CI 5-9) and patients with local recurrence only survived significantly longer (12 months, 95% CI 8-16) compared with patients with distant recurrence only (5 months, 95% CI 2-8) or distant plus local relapse (6 months, 95% CI 3-9; P = 0.04). A total of 78 patients received a second-line therapy after tumour recurrence: chemotherapy (n = 48), local radiotherapy (n = 9), surgery (n = 10) or a combination thereof (n = 11). Patients undergoing second-line treatment survived significantly longer compared with patients not receiving therapy (P < 0.0005). The median PRS after surgery was significantly longer than that of patients receiving chemo-, radio- or chemo-radiotherapy (P = 0.04)., Conclusions: Local recurrence of MPM remains the most frequent type of relapse even after multimodality treatment including MCR. In the present cohort, active treatment seems beneficial to the patient since surgical excision of local tumour relapse has good long-term outcome in selected patients. Thus, second-line treatment may prolong PRS; however, these results need to be confirmed in a prospective manner., (© The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)

Introduction: Treatment of malignant pleural mesothelioma (MPM) remains a clinical challenge. The aim of this study was to identify selection factors for allocation of MPM patients to multimodal therapy based on survival data from 12 years of experience., Methods: Eligible patients had MPM of all histological subtypes with clinical stage T1-3 N0-2 M0. Induction chemotherapy consisted of cisplatin/gemcitabine (cis/gem) or cisplatin/pemetrexed (cis/pem), followed by extrapleural pneumonectomy (EPP). Multivariate analysis was performed to assess independent prognosticators for overall survival (OS). A Multimodality Prognostic Score was developed based on clinical variables available before surgery., Results: From May 1999 to August 2011, 186 MPM patients were intended to be treated with induction chemotherapy followed by EPP. Hematologic toxicity was significantly less frequent after cis/pem compared to cis/gem, but there was no difference in response or OS between the regimens. One hundred and twenty-eight patients underwent EPP with a 30-day mortality of 4.7%. Fifty-two percent of the patients received adjuvant radiotherapy. The median OS of patients undergoing EPP was significantly longer with 22 months (95% confidence interval: 20-24) when compared to 11 months (9-12) for patients treated without EPP. A prognostic score was defined considering tumor volume, histology, C-reactive protein level, and response to chemotherapy that identified patient groups not benefitting from multimodality treatment which was confirmed in an independent cohort., Conclusion: Patients receiving induction chemotherapy followed by EPP for MPM of all histological subtypes and irrespective of nodal status showed a median survival of 22 months. A prognostic score is proposed to help patient allocation for surgery after validation in an independent cohort.

Background: The epithelioid and sarcomatoid histologic variants of malignant pleural mesothelioma (MPM) can be considered as E- and M-parts of the epithelial-mesenchymal transition (EMT) axis; the biphasic being an intermediate. EMT is associated with an increase of stem cell (SC) traits. We correlated the neural crest SC marker nestin and the EMT marker periostin with histology, type of neo-adjuvant chemotherapy (CT) and overall survival (OS) of MPM patients., Patients and Methods: Tumor tissues of a historic cohort 1 (320 patients) and an intended induction chemotherapy followed by extrapleural pneumonectomy (EPP) cohort 2 (145 patients) were immunohistochemically H-scored (intensity of immunoreactivity multiplied by frequency of stained cells). Paired chemo-naïve biopsies and -treated surgical specimens were available for 105/145 patients. CT included platinum/gemcitabine (Pla/Gem) or platinum/pemetrexed (Pla/Pem)., Results: Expression of any cytosolic nestin progressively increased from epithelioid to biphasic to sarcomatoid MPM in cohort 1, whereas the diagnostic markers calretinin and podoplanin decreased. In cohort 2, Pla/Pem CT increased the expression level of nestin in comparison to Pla/Gem, whereas the opposite was found for periostin. In Pla/Pem treated patients, nestin was higher in biphasic MPM compared to epithelioid. In addition to non-epithelioid histology, any expression of nestin in chemo-naïve biopsies (median overall survival: 22 vs. 17 months) and chemo-treated surgical specimens (18 vs. 12 months) as well as high periostin in biopsies (23 vs. 15 months) were associated with poor prognosis. In the multivariate survival analysis, any nestin expression in chemo-naïve biopsies proved to be an independent prognosticator against histology. In both pre- and post-CT situations, the combination of nestin or periostin expression with non-epithelioid histology was particularly/ dismal (all p-values <0.05)., Conclusions: The SC marker nestin and the EMT marker periostin allow for further prognostic stratification among histologic variants of MPM. Their expression level is influenced by neo-adjuvant chemotherapy.

Background: Several publications have suggested that induction chemotherapy followed by extrapleural pneumonectomy (EPP) for patients with malignant pleural mesothelioma (MPM) patients is associated with exceedingly high morbidity and mortality, and the role of EPP is controversially debated. The present retrospective study analyzed the perioperative outcome in 251 consecutively treated patients at three high-volume mesothelioma centers., Methods: 251 MPM patients completed EPP after platinum-based induction chemotherapy at three institutions for thoracic surgery over more than 10 years. The rates of 30-day and 90-day mortality and of major morbidities (pulmonary embolism, postoperative bleeding, acute respiratory distress syndrome, empyema, bronchopleural fistula (BPF), chylothorax, patch failure) were recorded. Perioperative outcome was correlated to risk factors such as smoking history (pack years), age at operation, body mass index, spirometry results, C-reactive protein, American Society of Anesthesiologists classification, chemotherapy regimen used, blood loss during operation, duration of operation, and characteristics of the tumor (laterality, histologic subtype, pT and pN stage) to find factors predicting 30-day and 90-day mortality or major morbidity., Results: The overall 30-day mortality was 5%. Within 90 days after operation, 8% of the patients died. The rates of 30-day and 90-day mortality were significantly higher in patients with high preoperative C-reactive protein values (p=0.001 and p<0.0005). The spirometry values forced expiratory volume in 1 second and forced vital capacity exhaled (FVCex) were both associated with 30-day and 90-day mortality (p=0.001 and p<0.0005; and p=0.002 and p<0.0005). Major morbidity occurred in 30% of the patients, significantly more often after right-sided EPP (p=0.01) and after longer operations (p<0.0005). Empyema (p<0.0005) and acute respiratory distress syndrome (p=0.02) were associated with longer duration of operation., Conclusions: EPP after induction chemotherapy is a demanding procedure but can be performed with acceptable morbidity and mortality if patients are well selected and treated at dedicated high-volume MPM centers., (Copyright © 2014 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)