Current issues in malignant pleural mesothelioma evaluation and management

Impact of guideline therapy on survival of patients with stage I-III epithelioid mesothelioma

Background

Modern treatment guidelines recommend multimodal therapy with at least chemotherapy and surgery for patients with potentially resectable epithelioid mesothelioma. This study evaluated guideline compliance for patients with stage I-III epithelioid mesothelioma and tested the hypothesis that guideline-concordant therapy improved survival.

Methods

The National Cancer Database was queried for patients with stage I-III epithelioid malignant pleural mesothelioma between 2004 and 2016. The impact of therapy was evaluated using logistic regression, Kaplan-Meier analysis, Cox-proportional hazards analysis, and propensity-scoring methods.

Results

During the study period, guideline-concordant therapy was used in 677 patients (19.1%), and 2,857 patients (80.8%) did not have guideline-concordant therapy. Younger age, being insured, living in a census tract with a higher income, clinical stage, and being treated at an academic or research program were all predictors of receiving guideline-concordant therapy in multivariable analysis. Guideline-concordant therapy yielded improved median survival [24.7 (22.4-26.1) vs. 13.7 (13.2-14.4) months] and 5-year survival [17.7% (14.7-21.3%) vs. 8.0% (7.0-9.3%)] (P<0.001), and continued to be associated with better survival in both multivariable analysis and propensity-matched analysis. In the patients who received guideline therapy, median survival [24.9 (21.9-27.2) vs. 24.5 (21.7-28.1) months] and 5-year survival [14.9% (10.9-20.2%) vs. 20.1% (16.0-25.4%)] was not significantly different between patients who underwent induction (n=304) versus adjuvant (n=373) chemotherapy (P=0.444).

Conclusions

Guideline-concordant therapy for potentially resectable epithelioid mesothelioma is associated with significantly improved survival but used in a minority of patients. The timing of chemotherapy with surgery in this study did not have a significant impact on overall survival.

MesoGraph: Automatic profiling of mesothelioma subtypes from histological images

Mesothelioma is classified into three histological subtypes, epithelioid, sarcomatoid, and biphasic, according to the relative proportions of epithelioid and sarcomatoid tumor cells present. Current guidelines recommend that the sarcomatoid component of each mesothelioma is quantified, as a higher percentage of sarcomatoid pattern in biphasic mesothelioma shows poorer prognosis. In this work, we develop a dual-task graph neural network (GNN) architecture with ranking loss to learn a model capable of scoring regions of tissue down to cellular resolution. This allows quantitative profiling of a tumor sample according to the aggregate sarcomatoid association score. Tissue is represented by a cell graph with both cell-level morphological and regional features. We use an external multicentric test set from Mesobank, on which we demonstrate the predictive performance of our model. We additionally validate our model predictions through an analysis of the typical morphological features of cells according to their predicted score.

Malignant Mesothelioma subtyping via sampling driven multiple instance prediction on tissue image and cell morphology data

Malignant Mesothelioma is a difficult to diagnose and highly lethal cancer usually associated with asbestos exposure. It can be broadly classified into three subtypes: Epithelioid, Sarcomatoid, and a hybrid Biphasic subtype in which significant components of both of the previous subtypes are present. Early diagnosis and identification of the subtype informs treatment and can help improve patient outcome. However, the subtyping of malignant mesothelioma, and specifically the recognition of transitional features from routine histology slides has a high level of inter-observer variability. In this work, we propose an end-to-end multiple instance learning (MIL) approach for malignant mesothelioma subtyping. This uses an adaptive instance-based sampling scheme for training deep convolutional neural networks on bags of image patches that allows learning on a wider range of relevant instances compared to max or top-N based MIL approaches. We also investigate augmenting the instance representation to include aggregate cellular morphology features from cell segmentation. The proposed MIL approach enables identification of malignant mesothelial subtypes of specific tissue regions. From this a continuous characterisation of a sample according to predominance of sarcomatoid vs epithelioid regions is possible, thus avoiding the arbitrary and highly subjective categorisation by currently used subtypes. Instance scoring also enables studying tumor heterogeneity and identifying patterns associated with different subtypes. We have evaluated the proposed method on a dataset of 234 tissue micro-array cores with an AUROC of 0.89±0.05 for this task. The dataset and developed methodology is available for the community at: https://github.com/measty/PINS.

A biomarker predicting unfavorable prognosis in malignant pleural mesothelioma: systemic immune–inflammation index

Aim: Malignant pleural mesothelioma (MPM) is an extremely mortal condition. Only a few prognostic biomarkers have been described for MPM. Our study looked into the association between patient survival and the Systemic Immune Inflammation Index (SII). Material and Method: A total of 158 patients who were admitted to our hospital between January 2013 and December 2022, and had a histopathologically confirmed diagnosis of MPM were included in the study. Before treatment, hematological parameters and SII were determined. A Spearman's correlation analysis was performed to analyze the correlation of mean survival with hematological parameters. Results: The study involved 158 patients in all. 70 patients had a history of smoking, the median age was 63 years, the mean survival time was 15.3 months, and 57.6% of the participants were men. The epithelioid type (84.2%) was the most prevalent histological subtype, and 29 patients had stage 4 illnesses. Of the participants, 84% had received chemotherapy, and 22% had received radiotherapy before. Among the 39 patients who had surgery, 5 had an extrapleural pneumonectomy. SII mean±sd was (1427.2±1207.3). The patients with stage 4 disease had significantly shorter survival (p=0.001). The patients who had surgery survived significantly longer (p=0.01). Hemoglobin (Hb) (r:0.21, p:0.01) and Hematocrit (Hct) (r:0.18, p:0.03) values showed weak positive correlations with mean survival. It was evident that mean survival got shorter as SII (r:-0.17, p:0.04) and neutrophil-lymphocyte ratio (NLR) (r:-0.19, p:0.02) values got higher. On the other hand, there was a strong positive association between mean survival and the lymphocyte-monocyte ratio (LMR) (r:0.21, p:0.01). When the parameters that had statistically significant differences among the groups were taken as control variables and the statistical analysis was re-performed, it was found that Hgb and Hct values as well as NLR and LMR ratios lost their significant correlations with survival. However, the SII ratio was still negatively correlated with survival (r:-0.16, p:0.04). Conclusion: Pretreatment SII is a noninvasive and easy-to-calculate biomarker that predicts the prognosis of MPM. It is negatively correlated with mean survival regardless of the tumor stage and surgical management.

Establishment and validation of nomograms to predict survival probability of advanced malignant pleural mesothelioma based on the SEER database and a Chinese medical institution

Objective

The purpose of this study was to build nomograms for predicting the survival of individual advanced pleural mesothelioma (MPM) patients using the Surveillance, Epidemiology, and End Results (SEER) database.

Methods

The 1251 patients enrolled from the SEER database were randomized (in a 7:3 ratio) to a training cohort and an internal validation cohort. Eighty patients were enrolled from the Harbin Medical University Cancer Hospital as the external validation cohort. Nomograms were constructed from variables screened by univariate or multivariate Cox regression analyses and evaluated by consistency indices (C-index), calibration plots, and receiver operating characteristic (ROC) curves. Patients from the SEER database who received chemotherapy alone and chemoradiotherapy were statistically paired using propensity score matching of the two groups and performed subgroup analysis in the screened variables.

Results

The nomograms are well-structured and well-validated prognostic maps constructed from four variables: gender, histology, AJCC stage, and treatment. All individuals were allocated into high-risk versus low-risk groups based on the median risk score of the training cohort, with the high-risk group having worse OS and CSS in all three cohorts (P<0.05). The outcomes of the subgroup analysis indicated that the advanced MPM patients receiving chemotherapy with or without local radiotherapy do not affect OS or CSS.

Conclusion

The accurate nomograms to predict the survival of patients with advanced MPM were built and validated based on an analysis of the SEER database with an external validation cohort. The study suggests that the additional local radiotherapy to chemotherapy does not increase the survival benefit of patients.

Examining the impact of physical function performance in predicting patient outcomes after lung-sparing surgery for malignant pleural mesothelioma

PURPOSE

The purpose of this study was to examine the impact of physical function performance and pulmonary function on patient outcomes after lung-sparing surgery for malignant pleural mesothelioma (MPM).

MATERIALS AND METHODS

A retrospective review of 54 patients with MPM from 2015 to 2020 was performed. The primary objective was to assess whether physical function, as measured by the Eastern Cooperative Oncology Group Performance Status (ECOG), and pulmonary function tests were predictive of postoperative patient outcomes (ventilator days, chest tube days, hospital length of stay). A secondary objective was to explore demographic and preoperative variables that best predict postoperative physical function and patient outcomes.

RESULTS

Data include 54 patients who underwent extended pleurectomy-decortication. Preoperative ECOG was a significant predictor of postoperative patient outcomes while preoperative lung function lacked predictive ability. Preoperative ECOG was also predictive of preoperative lung function. Age on the day of surgery was the best predictor of postoperative physical function, which was significantly reduced postoperatively.

CONCLUSIONS

Preoperative physical function performance was a significant predictor of postoperative outcomes. The results of our study highlight the importance of physical function in patients with MPM and support the need for early rehabilitation and further research to determine optimal rehabilitation interventions.IMPLICATIONS FOR REHABILITATIONPreoperative physical function can predict outcomes after lung-sparing surgery for malignant pleural mesothelioma (MPM).Physical function in patients with MPM should be carefully examined.To accurately reflect patients' abilities, patient assessment should include both patient-reported outcomes and performance-based measures.Patients with MPM should receive rehabilitation early after diagnosis and throughout the continuum of care.

Biological Pathways Associated With the Development of Pulmonary Toxicities in Mesothelioma Patients Treated With Radical Hemithoracic Radiation Therapy: A Preliminary Study

Radical hemithoracic radiotherapy (RHR), after lung-sparing surgery, has recently become a concrete therapeutic option for malignant pleural mesothelioma (MPM), an asbestos-related, highly aggressive tumor with increasing incidence and poor prognosis. Although the toxicity associated to this treatment has been reduced, it is still not negligible and must be considered when treating patients. Genetic factors appear to play a role determining radiotherapy toxicity. The aim of this study is the identification of biological pathways, retrieved through whole exome sequencing (WES), possibly associated to the development of lung adverse effects in MPM patients treated with RHR. The study included individuals with MPM, treated with lung-sparing surgery and chemotherapy, followed by RHR with curative intent, and followed up prospectively for development of pulmonary toxicity. Due to the strong impact of grade 3 pulmonary toxicities on the quality of life, compared with less serious adverse events, for genetic analyses, patients were divided into a none or tolerable pulmonary toxicity (NoSTox) group (grade ≤2) and a severe pulmonary toxicity (STox) group (grade = 3). Variant enrichment analysis allowed us to identify different pathway signatures characterizing NoSTox and Stox patients, allowing to formulate hypotheses on the protection from side effects derived from radiotherapy as well as factors predisposing to a worst response to the treatment. Our findings, being aware of the small number of patients analyzed, could be considered a starting point for the definition of a panel of pathways, possibly helpful in the management of MPM patients.

Malignant pleural mesothelioma: an update

Malignant mesotheliomas are rare types of cancers that affect the mesothelial surfaces, usually the pleura and peritoneum. They are associated with asbestos exposure, but due to a latency period of more than 30 years and difficult diagnosis, most cases are not detected until they reach advanced stages. Treatment options for this tumor type are very limited and survival ranges from 12 to 36 months. This review discusses the molecular physiopathology, current diagnosis, and latest therapeutic options for this disease.

Role of Cytology in the Current Guidelines for Malignant Mesothelioma: Largest Study from India

INTRODUCTION

Cytology provides crucial window for early diagnosis of malignant mesothelioma (MM) since it is often the first and easily available material for evaluation, resulting in early treatment. Still, its role is overlooked in the current treatment guidelines. The aim of this study is to determine the sensitivity of cytomorphology and role of subsequent ancillary techniques in diagnosing MM.

METHODS

This is a 5-year retrospective analysis of MM in the tertiary oncology center to determine sensitivity of cytomorphology and subsequent role of immunohistochemistry (IHC) in final diagnosis of MM according to the guidelines for cytopathologic diagnosis of epithelioid and mixed-type malignant mesothelioma (GCDMM) laid by International Mesothelioma Interest Group. Cytomorphology and immunocytochemistry from effusions and fine needle aspirations were analyzed.

RESULTS

Sixty-two of 128 cases of MM had cytology and cytomorphological criteria described in GCDMM were fulfilled in 61.3% cases. Architectural atypia was useful in identifying cases with low cytological atypia. Overall sensitivity of cytomorphology was 73.01%. Sensitivity of effusion cytology was 77.8%. Subsequent IHC on cell blocks revealed the sensitivity as 100% for mesothelin, calretinin, and cytokeratin 5/6; 87.5% for thrombomodulin; and 50% for WT1, while CEA and TTF1 showed 100% specificity. Treatment was given based on final diagnosis of MM given after IHC on cytology material in only 25.8% cases. However, it was possible in additional 35.5% cases. Mean survival was 10 months when diagnosed by cytology, compared to 7 months by histology.

CONCLUSIONS

Rather than ignoring the role of cytology in the diagnosis and treatment guidelines for MM, it is important to understand its strengths and limitations. Standardized guidelines in future can play an important role in more streamlined communication between cytopathologist and clinician.

Loco-regional staging of malignant pleural mesothelioma by integrated 18F-FDG PET/MRI

AIM

To examine the performance of 18F-FDG PET/MRI in the loco-regional staging of malignant pleural mesothelioma (MPM).

METHODS

Consecutive subjects with MPM undergoing pre-operative staging with 18F-FDG PET/CT who underwent a same day integrated 18F-FDG PET/MRI were prospectively studied. Clinical TNM staging (AJCC 7th edition) was performed separately and in consensus by two readers on the 18F-FDG PET/MRI studies, and compared with staging by 18F-FDG PET/CT, and with final pathological stage, determined by a combination of intra-operative and histological findings.

RESULTS

10 subjects (9 male, mean age 68 years) with biopsy-proven MPM (9 epithelioid tumours, 1 biphasic) were included. One subject underwent neo-adjuvant chemotherapy between imaging and surgery and was excluded from the clinical versus pathological stage analysis. Pathological staging was concordant with staging by 18F-FDG PET/MRI in 67% (n = 6) of subjects, and with 18F-FDG PET/CT staging in 33% (n = 3). Pathological T stage was concordant with 18F-FDG PET/MRI in 78% (n = 7), and with 18F-FDG PET/CT in 33% (n = 3) of subjects. Pathological N stage was concordant with both 18F-FDG PET/MRI and 18F-FDG PET/CT in 78% (n = 7) of cases. No subject had metastatic disease. There was good inter-observer agreement for overall PET/MRI staging (weighted kappa 0.63) with moderate inter-reader agreement for T staging (weighted kappa 0.59). All 6 subjects with prior talc pleurodesis demonstrated mismatch between elevated FDG uptake and restricted diffusion in areas of visible talc deposition.

CONCLUSION

Clinical MPM staging by 18F-FDG PET/MRI is feasible, and potentially provides more accurate loco-regional staging than PET/CT, particularly in T staging.

Survival analysis via nomogram of surgical patients with malignant pleural mesothelioma in the Surveillance, Epidemiology, and End Results database

Background

Malignant pleural mesothelioma (MPM) is a rare but aggressive tumor that originates from the pleura and has a poor prognosis. Eligible patients can benefit from surgery, but their survival is affected by many factors. Therefore, we created a graphic model that could predict the prognosis of surgically treated patients.

Methods

We retrospectively analyzed data from the Surveillance, Epidemiology, and End Results database from 2004 to 2014 to identify the key factors affecting the prognosis of surgically treated MPM patients. On this basis we built a nomogram to predict survival. We then evaluated the performance of the nomogram in a validation cohort.

Results

In a training cohort of 828 cases, independent prognostic factors, including age, gender, histological type, differentiation, N stage, chemotherapy, type of surgery, and lymph node dissection, were identified. We then developed a nomogram to evaluate individual patient survival. In Kaplan–Meier analysis, a higher score in the nomogram was associated with a worse prognosis. We also used a validation cohort consisting of 312 patients to evaluate the performance of the nomogram, which was well calibrated and had good discrimination ability, with concordance indices of 0.715 and 0.656 for the training and validation cohorts, respectively.

Conclusion

This study has improved our understanding of resected MPM and shown that key factors, including age and histological type, are associated with overall survival. The nomogram is a reliable tool that can help clinicians turn individualized prediction into reality and maximize patient benefit by identifying the most beneficial treatment approach.

Differential Survival Characteristics of Sarcomatoid Subtype in Biphasic Pleural Mesothelioma

BACKGROUND

Biphasic pleural mesothelioma (BPM) accounts for approximately 10% of all pleural mesothelioma. Our aim was to assess the clinical, radiologic, and pathologic factors impacting survival in BPM and to better identify patients most likely to benefit from active treatment.

METHODS

A 10-year retrospective review was made of 214 biopsy-proven BPM cases with minimum 2-year follow-up. Patients with insufficient tissue for analysis were excluded (n = 96). Clinical and pathologic factors were evaluated along with radiologic assessment of pleural thickness. Survival was measured from time of diagnosis. Univariable and multivariable predictors of survival were evaluated.

RESULTS

In all, 118 patients were included; 28 underwent pleurectomy/decortication, with 27 receiving additional modalities. Ninety patients underwent chemotherapy (n = 18) or radiotherapy alone (n = 9), 63 received combination therapy, and 27 received best supportive care. Median overall survival was 11.2 months (range, 0.3 to 36.2). At univariable analysis, pleurectomy/decortication (p = 0.0061), radiotherapy (p < 0.0001), and chemotherapy (p < 0.0001) were associated with superior survival when compared with best supportive care alone. Pleurectomy/decortication demonstrated 40% survival improvement compared with no surgery (p = 0.122). In a multivariable model, necrosis was negatively prognostic (hazard ratio 2.1, SE 0.76). Furthermore, increased sarcomatoid component was associated with worse survival without radiotherapy.

CONCLUSIONS

BPM prognosis remains poor despite multimodality treatment. Anticancer treatment is associated with superior outcome in this nonrandomized retrospective series. Our findings suggest superior survival for patients with a lower proportion of sarcomatoid disease, with selective benefit of radiotherapy in higher proportions of sarcomatoid disease. When planning active treatment, the potential survival benefits require balancing against associated morbidity and recovery period.

Biomarkers for early diagnosis of malignant mesothelioma: Do we need another moonshot?

Early diagnosis of malignant pleural mesothelioma (MPM) is a challenge for clinicians. The disease is usually detected in an advanced stage which precludes curative treatment. We assume that only new and non-invasive biomarkers allowing earlier detection will result in better patient management and outcome. Many efforts have already been made to find suitable biomarkers in blood and pleural effusions, but have not yet resulted in a valid and reproducible diagnostic one. In this review, we will highlight the strengths and shortcomings of blood and fluid based biomarkers and highlight the potential of breath analysis as a non-invasive screening tool for MPM. This method seems very promising in the early detection of diverse malignancies, because exhaled breath contains valuable information on cell and tissue metabolism. Research that focuses on breath biomarkers in MPM is in its early days, but the few studies that have been performed show promising results. We believe a breathomics-based biomarker approach should be further explored to improve the follow-up and management of asbestos exposed individuals.

Overview of treatment related complications in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive malignant neoplasm of the pleura related to asbestos exposure. Despite recent advances in therapy for MPM, the prognosis remains poor, with considerable treatment associated morbidity. Radiological assessment plays a central role in the timely identification and subsequent management of treatment related complications in MPM. This review highlights common and uncommon complications associated with and encountered in the post treatment phase.

BAP1, a tumor suppressor gene driving malignant mesothelioma

Like cancer generally, malignant mesothelioma (MM) is a genetic disease at the cellular level. DNA copy number analysis of mesothelioma specimens has revealed a number of recurrent sites of chromosomal loss, including 3p21.1, 9p21.3, and 22q12.2. The key inactivated driver genes located at 9p21.1 and 22q12.2 were discovered two decades ago as being the tumor suppressor loci CDKN2A and NF2, respectively. Only relatively recently was the BAP1 gene determined to be the driver gene at 3p21.1 that is somatically inactivated. In 2011, we reported germline mutations in BAP1 in two families with a high incidence of mesothelioma and other cancers such as uveal melanoma (UM). As a result of a flurry of research activity over the last 5-6 years, the BAP1 gene is now firmly linked causally to a novel tumor predisposition syndrome (TPDS) characterized by increased susceptibility to mesothelioma, UM, cutaneous melanoma (CM) and benign melanocytic tumors, as well as several other cancer types. Moreover, results from recent in vivo studies with genetically engineered Bap1-mutant mouse models and new functional studies have provided intriguing biological insights regarding BAP1's role in tumorigenesis. These and other recent findings offer new possibilities for novel preventative and therapeutic strategies for MM patients.

Intensity modulated radiation therapy after extra-pleural pneumonectomy for malignant pleural mesothelioma is feasible without fatal pulmonary toxicity and provides good survival

AIM

To analyze patterns of failure, toxicity, relapse-free survival (RFS), and overall survival (OS) in malignant pleural mesothelioma (MPM) patients treated with intensity-modulated radiation therapy following extrapleural pneumonectomy (EPP).

METHODS

We reviewed 18 charts of patients with MPM from 2005 to 2014 who underwent EPP followed by hemithoracic intensity-modulated radiation therapy. Intensity-modulated radiation therapy dose delivery adhered to published lung dose constraints. Kaplan-Meier curves were used to assess the RFS and OS. Median survival times are reported for both RFS and OS.

RESULTS

Median age was 65 years (range: 40-76 years). Chemotherapy was administered in four neo-adjuvant and seven adjuvant patients. Pathological American Joint Committee on Cancer stages II, III, IV, surgical margin, lympho-vascular space, pericardium, and chest wall involvement were seen in 3, 12, 3, 9, 7, 12 and 3 patients, respectively. The majority of the patients received 45 Gy in 25 fractions. The mean lung dose was 7.14 Gy (range: 5 Gy-9.3 Gy). The mean V20 was 2.23%. At a median follow-up of 3 years, eight patients were alive (44%); 10 experienced relapse (56%). Median RFS and OS were 24.4 months (95% CI: >16.3 months) and 38.2 months (95% CI: 17.4-78.1 months), respectively. Acute toxicities were fatigue, dermatitis, nausea, esophagitis/dysphagia, cough, and dyspnea on exertion. No grade III, IV, or fatal pulmonary toxicities were observed.

CONCLUSION

Intensity-modulated radiation therapy following EPP for MPM resulted in RFS and OS comparable to the published literature without significant toxicity.

5T4 oncofoetal antigen: an attractive target for immune intervention in cancer

The natural history of a patient's cancer is often characterised by genetic diversity and sequential sweeps of clonal dominance. It is therefore not surprising that identifying the most appropriate tumour-associated antigen for targeted intervention is challenging. The 5T4 oncofoetal antigen was identified by searching for surface molecules shared between human trophoblast and cancer cells with the rationale that they may function to allow survival of the foetus as a semi-allograft in the mother or a tumour in its host. The 5T4 protein is expressed by many different cancers but rarely in normal adult tissues. 5T4 molecules are 72 kD, heavily N-glycosylated proteins with several leucine-rich repeats which are often associated with protein-protein interactions. 5T4 expression is associated with the directional movement of cells through epithelial mesenchymal transition, potentiation of CXCL12/CXCR4 chemotaxis and inhibition of canonical Wnt/beta-catenin while favouring non-canonical pathway signalling; all processes which help drive the spread of cancer cells. The selective pattern of 5T4 tumour expression, association with a tumour-initiating phenotype plus a mechanistic involvement with cancer spread have underwritten the clinical development of different immunotherapeutic strategies including a vaccine, a tumour-targeted superantigen and an antibody drug conjugate. In addition, a chimeric antigen receptor T cell approach targeting 5T4 expressing tumour cells is in pre-clinical development. A key challenge will include how best to combine each 5T4 targeted immunotherapy with the most appropriate standard of care treatment (or adjunct therapy) to maximise the recovery of immune control and ultimately eliminate the tumour.

Pilot and Feasibility Trial Evaluating Immuno-Gene Therapy of Malignant Mesothelioma Using Intrapleural Delivery of Adenovirus-IFNα Combined with Chemotherapy

PURPOSE

"In situ vaccination" using immunogene therapy has the ability to induce polyclonal antitumor responses directed by the patient's immune system.

EXPERIMENTAL DESIGN

Patients with unresectable malignant pleural mesothelioma (MPM) received two intrapleural doses of a replication-defective adenoviral vector containing the human IFNα2b gene (Ad.IFN) concomitant with a 14-day course of celecoxib followed by chemotherapy. Primary outcomes were safety, toxicity, and objective response rate; secondary outcomes included progression-free and overall survival. Biocorrelates on blood and tumor were measured.

RESULTS

Forty subjects were treated: 18 received first-line pemetrexed-based chemotherapy, 22 received second-line chemotherapy with pemetrexed (n = 7) or gemcitabine (n = 15). Treatment was generally well tolerated. The overall response rate was 25%, and the disease control rate was 88%. Median overall survival (MOS) for all patients with epithelial histology was 21 months versus 7 months for patients with nonepithelial histology. MOS in the first-line cohort was 12.5 months, whereas MOS for the second-line cohort was 21.5 months, with 32% of patients alive at 2 years. No biologic parameters were found to correlate with response, including numbers of activated blood T cells or NK cells, regulatory T cells in blood, peak levels of IFNα in blood or pleural fluid, induction of antitumor antibodies, nor an immune-gene signature in pretreatment biopsies.

CONCLUSIONS

The combination of intrapleural Ad.IFN, celecoxib, and chemotherapy proved safe in patients with MPM. OS rate was significantly higher than historical controls in the second-line group. Results of this study support proceeding with a multicenter randomized clinical trial of chemo-immunogene therapy versus standard chemotherapy alone. Clin Cancer Res; 22(15); 3791-800. ©2016 AACR.

Immune biomarkers PD-1/PD-L1 and TLR3 in malignant pleural mesotheliomas

Malignant pleural mesothelioma (MPM) is an aggressive tumor with no effective therapy. However PD-L1/PD-1 immunity checkpoint therapies gave encouraging results; TLR3 is a programmed death factor, which triggering up-regulates PD-L1. As PD-1/PD-L1 blocking antibodies could restore antitumor immune responses alone or in combination with TLR3 agonists, we investigated PD-L1/PD-1 and TLR3 expressions in MPM to select patients for immunotherapy. Sixty-eight pleural surgical specimens, including 58 MPM (epithelioid, n = 34; biphasic, n = 11; sarcomatoid, n = 13) and 10 benign lesions, were studied. PD-L1 expression was assessed using E1L3N and SP142 clones in tumor cells (TCs) and in tumor-infiltrating lymphocytes (TILs) (positivity threshold of 1%), and compared with overall survival. PD-1, CD3 and CD8 expression by TILs, and TLR3 expression by TCs were analyzed concomitantly. PD-L1 was more expressed by sarcomatoid subtype than by other MPM (62% versus 23% and 9% for E1L3N; 38% versus 11% for SP142) (P = .01 and .04, respectively). Specificity and sensitivity of E1L3N and SP142 were of 53% and 98%, and 90% and 86%, respectively. PD-L1 expression by TILs and TCs correlated for SP142 (P = .023), and PD-L1 SP142 expression by TCs was associated with shorter overall survival (P = .016). TLR3 was expressed in most MPM, but weakly in sarcomatoid MPM. We confirm by comparing two commercially available antibodies that PD-L1 expression is higher in sarcomatoid MPM and correlates with a shorter survival. Whereas TLR3 agonists could be tested in MPM expressing TLR3, the sarcomatoid subtype could benefit from anti-PD-L1/PD-1 therapies alone or in combination.

Impact of mesothelioma histologic subtype on outcomes in the Surveillance, Epidemiology, and End Results database

BACKGROUND

This study was conducted to determine how malignant pleural mesothelioma (MPM) histology was associated with the use of surgery and survival.

METHODS

Overall survival of patients with stage I-III epithelioid, sarcomatoid, and biphasic MPM in the Surveillance, Epidemiology, and End Results database from 2004-2010 was evaluated using multivariate Cox proportional hazards models.

RESULTS

Of 1183 patients who met inclusion criteria, histologic subtype was epithelioid in 811 patients (69%), biphasic in 148 patients (12%), and sarcomatoid in 224 patients (19%). Median survival was 14 mo in the epithelioid group, 10 mo in the biphasic group, and 4 mo in the sarcomatoid group (P < 0.01). Cancer-directed surgery was used more often in patients with epithelioid (37%, 299/811) and biphasic (44%, 65/148) histologies as compared with patients with sarcomatoid histology (26%, 58/224; P < 0.01). Among patients who underwent surgery, median survival was 19 mo in the epithelioid group, 12 mo in the biphasic group, and 4 mo in the sarcomatoid group (P < 0.01). In multivariate analysis, surgery was associated with improved survival in the epithelioid group (hazard ratio [HR] 0.72; P < 0.01) but not in biphasic (HR 0.73; P = 0.19) or sarcomatoid (HR 0.79; P = 0.18) groups.

CONCLUSIONS

Cancer-directed surgery is associated with significantly improved survival for MPM patients with epithelioid histology, but patients with sarcomatoid and biphasic histologies have poor prognoses that may not be favored by operative treatment. The specific histology should be identified before treatment, so that surgery can be offered to patients with epithelioid histology, as these patients are most likely to benefit.