UV1 telomerase vaccine with ipilimumab and nivolumab as second line treatment for pleural mesothelioma - A phase II randomised trial

PURPOSE

The NIPU-trial investigates the effect of adding the telomerase vaccine UV1 to treatment with ipilimumab and nivolumab for patients with pleural mesothelioma (PM).

METHODS

In this phase 2 open-label trial, patients with PM progressing after first-line chemotherapy were randomised to receive ipilimumab and nivolumab alone (arm B) or combined with UV1 (arm A). The primary endpoint was progression-free survival (PFS) as determined by BICR. It was estimated that 69 PFS events were needed to detect a hazard ratio (HR) of 0.60 with 80% power and a one-sided alpha level of 0.10.

RESULTS

118 patients were randomised. The median PFS determined by blinded independent central review (BICR) was 4.2 months (95%CI 2.9-9.8) in arm A and 4.7 months (95%CI 3.9-7.0) in arm B (HR 1.01, 80%CI 0.75-1.36 P = 0.979), after a median follow-up of 12.5 months (95%CI 9.7-15.6). The investigator-determined median PFS was 4.3 months (95%CI 3.0-6.8) in arm A and 2.9 months (95%CI 2.4-5.5) in arm B (HR 0.60, 80%CI 0.45-0.81 P = 0.025). Confirmed objective response rate (ORR) by BICR was 31% in arm A and 16% in arm B (odds ratio 2.44 80%CI 1.35-4.49 P = 0.056). After a median follow-up time of 17.3 months (95%CI 15.8-22.9), the OS was 15.4 months (95%CI 11.1-22.6) in arm A and 11.1 months (95%CI 8.8-18.1) in arm B, (HR 0.73, 80%CI 0.53-1.0, P = 0.197).

CONCLUSION

The primary endpoint was not met. Predefined analyses of response rates are in favour of adding the vaccine.

Brief Report: Real-World Toxicity and Survival of Combination Immunotherapy in Pleural Mesothelioma-RIOMeso

BACKGROUND

Australia has one of the highest rates of asbestos-associated diseases. Mesothelioma remains an area of unmet need with a 5-year overall survival of 10%. First-line immunotherapy with ipilimumab and nivolumab is now a standard of care for unresectable pleural mesothelioma following the CheckMate 743 trial, with supportive data from the later line single-arm MAPS2 trial. RIOMeso evaluates survival and toxicity of this regimen in real-world practice.

METHODS

Demographic and clinicopathologic data of Australian patients treated with ipilimumab and nivolumab in first- and subsequent-line settings for pleural mesothelioma were collected retrospectively. Survival was reported using the Kaplan-Meier method and compared between subgroups with the log-rank test. Toxicity was investigator assessed using Common Terminology Criteria for Adverse Events version 5.0.

RESULTS

A total of 119 patients were identified from 11 centers. The median age was 72 years, 83% were male, 92% had Eastern Cooperative Oncology Group less than or equal to 1, 50% were past or current smokers, and 78% had known asbestos exposure. In addition, 50% were epithelioid, 19% sarcomatoid, 14% biphasic, and 17% unavailable. Ipilimumab and nivolumab were used first line in 75% of patients. Median overall survival (mOS) was 14.5 months (95% confidence interval [CI]: 13.0-not reached [NR]) for the entire cohort. For patients treated first line, mOS was 14.5 months (95% CI: 12.5-NR) and in second- or later-line patients was 15.4 months (95% CI: 11.2-NR). There was no statistically significant difference in mOS for epithelioid patients compared with nonepithelioid (19.1 mo [95% CI: 15.4-NR] versus 13.0 mo [95% CI: 9.7-NR], respectively, p = 0.064). Furthermore, 24% of the patients had a Common Terminology Criteria for Adverse Events grade greater than or equal to 3 adverse events, including three treatment-related deaths. Colitis was the most frequent adverse event.

CONCLUSIONS

Combination immunotherapy in real-world practice has poorer survival outcomes and seems more toxic compared with clinical trial data. This is the first detailed report of real-world survival and toxicity outcomes using ipilimumab and nivolumab treatment of pleural mesothelioma.

Pediatric, Adolescent and Young Adult (AYA) Peritoneal and Pleural Mesothelioma: A National Cancer Database Review

PURPOSE

Malignant peritoneal and pleural mesothelioma are rare in young patients, with a paucity of data regarding clinical characteristics and outcomes. We aimed to describe the clinical characteristics, treatment strategies, and outcomes for pediatric and adolescent/young adult (AYA) patients.

METHODS

The National Cancer Database (NCDB) was queried for malignant peritoneal and pleural mesothelioma in pediatric and AYA patients (ages 0-39) from 2004 to 2019. Stratification was performed for pediatric (age 0-21) and young adult (age 22-39) patients. Chi-squared, multivariable cox regression, and Kaplan-Meier analyses were performed.

RESULTS

We identified 570 total patients, 46 pediatric and 524 young adult, with mesothelioma (363 peritoneal and 207 pleural). There were significant differences in sex distribution as patients with peritoneal mesothelioma were more frequently female (63.1%). Patients with peritoneal mesothelioma were more likely to have radical surgery compared to pleural mesothelioma (56.7% v. 24.6%, respectively). A majority of patients with peritoneal and pleural mesothelioma received chemotherapy (66.4% and 61.4%, respectively). For peritoneal mesothelioma, surgical resection was associated with improved overall survival, whereas male sex, neoadjuvant chemotherapy, and radiation were associated with worse overall survival. For pleural mesothelioma, intraoperative chemotherapy was associated with improved overall survival, whereas Black race was associated with worse overall survival. Mean overall survival was greater for patients with peritoneal mesothelioma (125 months) compared to those with pleural mesothelioma (69 months), which remained significant after stratification of pediatric and young adult patients.

CONCLUSION

By analyzing a large cohort of pediatric and AYA mesothelioma, this study highlights clinical, prognostic, and survival differences between peritoneal and pleural disease.

LEVEL OF EVIDENCE

Level III.

TYPE OF STUDY

Retrospective.

An overview on multimodal imaging for the diagnostic workup of pleural mesothelioma

Pleural mesothelioma (PM) is an aggressive disease that has a strong causal relationship with asbestos exposure and represents a major challenge from both a diagnostic and therapeutic viewpoint. Despite recent improvements in patient care, PM typically carries a poor outcome, especially in advanced stages. Therefore, a timely and effective diagnosis taking advantage of currently available imaging techniques is essential to perform an accurate staging and dictate the most appropriate treatment strategy. Our aim is to provide a brief, but exhaustive and up-to-date overview of the role of multimodal medical imaging in the management of PM.

Long-Term Survival Analysis of Pleural Mesothelioma Patients Undergoing Surgery: Brief Report From a Tertiary Referral Centre

OBJECTIVES

to date, no consensus has been reached on the surgical gold-standard in pleural mesothelioma (PM). We retrospectively reviewed our experience as a tertiary referral centre, to compare short- and long-term survival of PM patients undergoing different types of surgery.

METHODS

in retrospective, observational, single-centre study, we analysed all the patients histologically diagnosed with PM undergoing surgical procedures with palliative or curative intent at IRCCS Istituto Nazionale dei Tumori of Milan, Italy, from January 2003 to December 2020. The primary study endpoint was 10-year overall survival (OS) in three different types of resections: extra-pleural-pneumonectomy (EPP), pleurectomy/decortication (P/D), partial-pleurectomy/pleural-biopsy (PP/B). Secondary endpoints were postoperative hospital stay and postoperative 30-day and 90-day mortality rates. The survival function was estimated using Kaplan-Meier, and the Log-rank test was used for testing differences. Univariable and Multivariable Cox regression models were implemented to estimate Hazard Ratio (HR) for all variables of interest.

RESULTS

243 consecutive patients were enrolled, EPP was performed in 49 (20.2%), P/D in 58 (23.8%), PP/B in 136 (56.0%) patients. The median follow-up time was 19.8 months. 10-year OS was significantly better for P/D group (16%, Log-Rank test p<0.0001) compared to PP/B (1.8%) and EPP (0%). No statistically significant differences were found among the 3 surgical groups in 30- and 90-day mortality rates. At multivariable analysis, gender (male, HR=1.58), type of resection (P/D, HR=0.55) and surgery date (recent years, HR=0.61) were found to be independent prognostic factors for OS.

CONCLUSIONS

in PM, lung-sparing curative approach (e.g. P/D) should be preferred in highly selected patients and in highly experienced centres, whenever appropriate. Anyway, when P/D is not indicated, adopting palliative/conservative management (e.g. PP/B) could ensure comparable results as extremely aggressive surgeries (e.g. EPP). The aim of surgery in PM should not be reaching complete resection, but rather accomplishing significant resection allowing to complete the multimodality treatment in highly selected patients in experienced centers.

Established and new treatment roadmaps for pleural mesothelioma: opinions of the Turkish Collaborative Group

Pleural mesothelioma (PM) is a cancer of the pleural surface, which is aggressive and may be rapidly fatal. PM is a rare cancer worldwide, but is a relatively common disease in Turkey. Asbestos exposure is the main risk factor and the most common underlying cause of the disease. There have been significant improvements in diagnoses and treatments of many malignancies; however, there are still therapeutic challenges in PM. In this review, we aimed to increase the awareness of health care professionals, oncologists, and pulmonologists by underlining the unmet needs of patients with PM and by emphasizing the need for a multidisciplinary treatment and management of PM. After reviewing the general information about PM, we further discuss the treatment options for patients with PM using immunotherapy and offer evidence for improvements in the clinical outcomes of these patients because of these newer treatment modalities.

Krebs von den Lungen 6 (KL-6) is a novel diagnostic and prognostic biomarker in pleural mesothelioma

OBJECTIVES

Pleural mesothelioma (PM) is a rare disease with dismal outcome. Systemic treatment options include chemotherapy and immunotherapy, but biomarkers for treatment personalization are missing. The only FDA-approved diagnostic biomarker is the soluble mesothelin-related protein (SMRP). Krebs von den Lungen-6 (KL-6) is a human mucin 1 (MUC1) glycoprotein, which has shown diagnostic and prognostic value as a biomarker in other malignancies. The present study investigated whether KL-6 can serve as a diagnostic and/or prognostic biomarker in PM.

MATERIALS AND METHODS

Using a fully-automated chemiluminescence enzyme immunoassay (CLEIA) for KL-6 and SMRP, pleural effusion samples from 87 consecutive patients with PM and 25 patients with non-malignant pleural disorders were studied. In addition, KL-6 and SMRP levels were determined in corresponding patient sera, and in an independent validation cohort (n = 122). MUC1 mRNA and protein expression, and KL-6 levels in cell line supernatants were investigated in PM primary cell lines in vitro.

RESULTS

PM patients had significantly higher KL-6 levels in pleural effusion than non-malignant controls (AUC 0.78, p < 0.0001). Among PM patients, levels were highest in those with epithelioid or biphasic histologies. There was a strong positive correlation between pleural effusion levels of KL-6 and SMRP (p < 0.0001). KL-6 levels in sera similarly associated with diagnosis of PM, however, to a lesser extent (AUC 0.71, p = 0.008). PM patients with high pleural effusion KL-6 levels (≥303 IU/mL) had significantly better overall survival (OS) compared to those with low KL-6 levels (HR 0.51, p = 0.004). Congruently, high tumor cell MUC1 mRNA expression in primary cell lines associated with prolonged corresponding patient OS (HR 0.35, p = 0.004). These findings were confirmed in an independent validation cohort.

CONCLUSION

This is the first study demonstrating KL-6 as a potential novel liquid-based diagnostic and prognostic biomarker in PM.

Targeting YB-1 via entinostat enhances cisplatin sensitivity of pleural mesothelioma in vitro and in vivo

Pleural mesothelioma (PM) is characterized by poor prognosis and limited therapeutic options. Y-box-binding protein 1 (YB-1) was shown to drive growth and migration of PM cells. Here, we evaluated the effect of genetic and pharmacological targeting of YB-1 on PM growth and response to cisplatin and radiation treatment. YB-1 knockdown via siRNA resulted in reduced PM cell growth, which significantly correlated with wt BAP1 and mutant NF2 and P53 status. Entinostat inhibited YB-1 deacetylation and its efficacy correlated with YB-1 knockdown-induced growth inhibition in 20 PM cell lines. Tumor growth inhibition by siRNA as well as entinostat was confirmed in mouse xenotransplant models. Furthermore, both YBX1-targeting siRNA and entinostat enhanced sensitivity to cisplatin and radiation. In particular, entinostat showed strong synergistic interactions with cisplatin which was linked to significantly increased cellular platinum uptake in all investigated cell models. Importantly, in a mouse model, the combination of cisplatin and entinostat also resulted in stronger growth inhibition than each treatment alone. Our study highlights YB-1 as an attractive target in PM and demonstrates that targeting YB-1 via entinostat is a promising approach to enhance cisplatin and radiation sensitivity.

[Reconocimiento del mesotelioma de pleura como enfermedad profesional en la Comunidad Valenciana de 2012 a 2018.]

OBJECTIVE

Pleural mesothelioma is a neoplasm almost exclusively attributed to occupational exposure to asbestos and is legally considered an occupational disease. Nevertheless, only a few cases achieve that official recognition. The objective of this work was to describe and analyse this issue, and to identify the major obstacles to its recognition.

METHODS

A descriptive and retrospective epidemiological study of data was carried out, including figures and some characteristics, of all patients with pleural mesothelioma registered in the official health and labor registries of the Valencian Community from 2012 to 2018, using frequencies, proportions, and incidence rates.

RESULTS

There were large differences between the two sets of data collected in the different registries, especially regarding the number of cases. During the seven years of data examined, 590 pleural mesotheliomas were diagnosed in the Valencian public health system. Of these, the number of cases that were related to occupational exposure was at least 437. Despite the legal duty of doctors to report such cases, only 31 were reported as suspected occupational disease (7.09%), of which only 13 were ultimately officially recognized as such. It was estimated that the annual economic overcost to the public system of unrecognised patients with this occupational disease by was 2,2270,520 euros.

CONCLUSIONS

Only a small proportion of occupational mesotheliomas are officially recognized as such. This has important health care and economic repercussions for the individuals involved as well as for the public health system.

Clinically Occult Diffuse Pleural Mesothelioma in Patients Presenting With Spontaneous Pneumothorax

OBJECTIVES

To report histologic features of unsuspected diffuse pleural mesothelioma (DPM) in surgical specimens for pneumothorax and demonstrate how ancillary markers support a diagnosis of malignancy in this context. We explored whether pneumothorax may be a clinical manifestation of mesothelioma in situ (MIS).

METHODS

A single-institution database search identified patients who underwent surgical resection for spontaneous pneumothorax (n = 229) and/or were diagnosed with DPM (n = 88) from 2000 to 2020.

RESULTS

Spontaneous pneumothorax without clinical, radiologic, or intraoperative suspicion of mesothelioma was the initial presentation in 2 (2.3%) of 88 patients diagnosed with DPM. This represented 0.9% (2/229) of all patients undergoing surgical management of pneumothorax but accounted for a larger proportion of older patients (12.5% older than 70 years). Immunohistochemistry for BAP-1 and/or MTAP confirmed the diagnosis of DPM in 2 cases. Mesothelioma in situ was identified retrospectively by immunohistochemistry in 1 case of spontaneous pneumothorax from a 77-year-old man who developed invasive DPM 25 months later. No additional cases of MIS were identified in 19 surgical lung resections for spontaneous pneumothorax.

CONCLUSIONS

Histologic examination of bleb resections with ancillary testing for cases with ambiguous features is essential for detection of early DPM. It is uncertain whether spontaneous pneumothorax may represent a clinical manifestation of MIS.

European Epidemiology of Pleural Mesothelioma-Real-Life Data From a Joint Analysis of the Mesoscape Database of the European Thoracic Oncology Platform and the European Society of Thoracic Surgery Mesothelioma Database

INTRODUCTION

Pleural mesothelioma (PM) is an aggressive malignancy with increasing prevalence and poor prognosis. Real-life data are a unique approach to reflect the reality of PM epidemiology, treatment, and prognosis in Europe.

METHODS

A joint analysis of the European Thoracic Oncology Platform Mesoscape and the European Society of Thoracic Surgeons (ESTS) databases was performed to better understand the characteristics and epidemiology of PM, including histologic subtype, staging, and treatment. Overall survival (OS) was assessed, adjusting for parameters of clinical interest.

RESULTS

The analysis included 2766 patients (Mesoscape: 497/10 centers/ESTS: 2269/77 centers). The primary histologic subtype was epithelioid (71%), with 57% patients on stages III to IV. Within Mesoscape, the patients received either multimodality (59%) or palliative intention treatment (41%). The median follow-up was 47.2 months, on the basis of 1103 patients (Mesoscape: 491/ESTS: 612), with 823 deaths, and median OS was 17.4 months. In multivariable analysis, female sex, epithelioid subtype, and lower stage were associated with longer OS, when stratifying by cohort, age, and Eastern Cooperative Oncology Group Performance Status. Within Mesoscape, multimodality treatment including surgery was predictive of longer OS (hazard ratio = 0.56, 95% confidence interval: 0.45-0.69), adjusting for sex, histologic subtype, and Eastern Cooperative Oncology Group Performance Status. Overall, surgical candidates with a macroscopic complete resection had a significantly longer median OS compared with patients with R2 (25.2 m versus 16.4 m; log-rank p < 0.001).

CONCLUSIONS

This combined European Thoracic Oncology Platform/ESTS database analysis offers one of the largest databases with detailed clinical and pathologic outcome. Our finding reflects a benefit for selected patients that undergo multimodality treatment, including macroscopic complete resection, and represents a valuable resource to inform the epidemiology and treatment options for individual patients.

Diffuse malignant peritoneal mesothelioma presenting as small bowel obstruction

Mesotheliomas are aggressive malignant tumors which can occur most commonly in the pleural space, however can occur in the peritoneum in those with an extensive history of asbestos exposure. Primary peritoneal mesothelioma is relatively rare and is a fatal diagnosis. The prognosis of primary peritoneal mesothelioma is very poor and individuals are at high risk of developing mesothelioma in another cavity within the first year after initial diagnosis. Herein, we present a case of primary peritoneal mesothelioma, presenting as small bowel obstruction.

Pleural mesothelioma: a snapshot of emerging drug targets and opportunities for non-surgical therapeutic advancement

INTRODUCTION

Pleural mesothelioma is a rare and aggressive cancer originating in the pleura, with a devastating prognosis and limited treatment options. There have been significant advancements in the management of this disease in recent years. Since 2021, nivolumab and ipilimumab immune checkpoint inhibitors have become the new standard of care for first-line treatment of pleural mesothelioma.

AREAS COVERED

While a combination of chemotherapy and immune checkpoint inhibitors appears to be the next step, targeted therapies are emerging thanks to our understanding of the oncogenesis of pleural mesothelioma. Moreover, several new strategies are currently being investigated, including viral therapy, antibody-drug conjugates, and even cell therapies with CAR-T cells or dendritic cells. In this review, we will explore the various future opportunities that could potentially transform patients' lives in light of the clinical trials that have been conducted.

EXPERT OPINION

Future clinical studies aim to rebiopsy patients after disease progression to identify new molecular alterations and to be associated with ancillary studies, guiding subsequent therapy decisions. Predicting and investigating treatment resistance mechanisms will lead to innovative approaches and improved treatment outcomes.

[Clinical analysis of combined immunotherapy in patients with malignant pleural mesothelioma]

Objective: To observe the present situation, efficacy and safety of immunotherapy in patients with malignant pleural mesothelioma (MPM). Methods: The data of 39 patients with MPM in two centers from 2016 to 2021 were collected and the efficacy and safety were evaluated. According to the application of immune checkpoint inhibitors (ICIs), these patients, whose median clinical follow-up amounting to 18.97 months, were divided into immunotherapy group (19 cases) and control group (20 cases). Kaplan-Meier method and Log-rank test were used for the survival analysis. Results: The objective response rate (ORR) and the disease control rate (DCR) in the immunotherapy group is 21.05% and 79.0% respectively, compared with 10.0% and 55.0% in the control group; and the difference was not statistically significant (P>0.05). The median overall survival (OS) in the immunotherapy group was significantly longer than that in the control group (14.53 months vs 7.07 months, P=0.015), but there was no significant difference in the median progression free survival (PFS) between two groups (4.80 months vs 2.03 months, P=0.062). Single factor survival analysis showed that the nature of pleural effusion, pathological subtype and the efficacy of immunotherapy were related to both PFS and OS of the patients with MPM (P<0.05). The incidence of adverse reactions in immunotherapy group was 89.5% (17 out of 19 cases), and the most common adverse event was hematological toxicity (9 cases), followed by nausea and vomiting (7 cases), fatigue (6 cases) and skin damage (6 cases). Five patients had immune checkpoint inhibitors (ICIs) related adverse reactions with grade 1-2. Conclusions: Patients with MPM have begun to receive immunotherapy in more than 2-line mainly combined chemotherapy in the real world, and the median treatment line is 2-line. Either combined with chemotherapy or anti-angiogenesis therapy, ICI inhibitors have significant efficacy, controllable adverse events and good clinical value.

Novel therapeutic approaches for pleural mesothelioma identified by functional ex vivo drug sensitivity testing

OBJECTIVES

Pleural mesothelioma (PM) is an aggressive malignancy with limited treatment options. The first-line therapy has remained unchanged for two decades and consists of pemetrexed in combination with cisplatin. Immune-checkpoint inhibitors (nivolumab plus ipilimumab) have high response rates, resulting in recent updates in treatment recommendations by the U.S. Food and Drug Administration. However, the overall benefits of combination treatment are modest, suggesting that other targeted therapy options should be investigated.

MATERIALS AND METHODS

We employed high-throughput drug sensitivity and resistance testing on five established PM cell lines using 527 cancer drugs in a 2D setting. Drugs of the greatest potential (n = 19) were selected for further testing in primary cell models derived from pleural effusions of seven PM patients.

RESULTS

All established and primary patient-derived PM cell models were sensitive to the mTOR inhibitor AZD8055. Furthermore, another mTOR inhibitor (temsirolimus) showed efficacy in most of the primary patient-derived cells, although a less robust effect was observed when compared with the established cell lines. Most of the established cell lines and all patient-derived primary cells exhibited sensitivity to the PI3K/mTOR/DNA-PK inhibitor LY3023414. The Chk1 inhibitor prexasertib showed activity in 4/5 (80%) of the established cell lines and in 2/7 (29%) of the patient-derived primary cell lines. The BET family inhibitor JQ1 showed activity in four patient-derived cell models and in one established cell line.

CONCLUSION

mTOR and Chk1 pathways had promising results with established mesothelioma cell lines in an ex vivo setting. In patient-derived primary cells, drugs targeting mTOR pathway in particular showed efficacy. These findings may inform novel treatment strategies for PM.

Mesothelioma-associated fibroblasts enhance proliferation and migration of pleural mesothelioma cells via c-Met/PI3K and WNT signaling but do not protect against cisplatin

BACKGROUND

Pleural mesothelioma (PM) is an aggressive malignancy with poor prognosis. Unlike many other cancers, PM is mostly characterized by inactivation of tumor suppressor genes. Its highly malignant nature in absence of tumor driving oncogene mutations indicates an extrinsic supply of stimulating signals by cells of the tumor microenvironment (TME). Cancer-associated fibroblasts (CAFs) are an abundant cell type of the TME and have been shown to drive the progression of several malignancies. The aim of the current study was to isolate and characterize patient-derived mesothelioma-associated fibroblasts (Meso-CAFs), and evaluate their impact on PM cells.

METHODS

Meso-CAFs were isolated from surgical specimens of PM patients and analyzed by array comparative genomic hybridization, next generation sequencing, transcriptomics and proteomics. Human PM cell lines were retrovirally transduced with GFP. The impact of Meso-CAFs on tumor cell growth, migration, as well as the response to small molecule inhibitors, cisplatin and pemetrexed treatment was investigated in 2D and 3D co-culture models by videomicroscopy and automated image analysis.

RESULTS

Meso-CAFs show a normal diploid genotype without gene copy number aberrations typical for PM cells. They express CAF markers and lack PM marker expression. Their proteome and secretome profiles clearly differ from normal lung fibroblasts with particularly strong differences in actively secreted proteins. The presence of Meso-CAFs in co-culture resulted in significantly increased proliferation and migration of PM cells. A similar effect on PM cell growth and migration was induced by Meso-CAF-conditioned medium. Inhibition of c-Met with crizotinib, PI3K with LY-2940002 or WNT signaling with WNT-C59 significantly impaired the Meso-CAF-mediated growth stimulation of PM cells in co-culture at concentrations not affecting the PM cells alone. Meso-CAFs did not provide protection of PM cells against cisplatin but showed significant protection against the EGFR inhibitor erlotinib.

CONCLUSIONS

Our study provides the first characterization of human patient-derived Meso-CAFs and demonstrates a strong impact of Meso-CAFs on PM cell growth and migration, two key characteristics of PM aggressiveness, indicating a major role of Meso-CAFs in driving PM progression. Moreover, we identify signaling pathways required for Meso-CAF-mediated growth stimulation. These data could be relevant for novel therapeutic strategies against PM.

Malignant peritoneal mesothelioma

Malignant peritoneal mesothelioma (MPM) is a rare, life-threatening malignant tumor. We present a report of a rare case of a 67-year-old male patient with MPM and severe abdominal pain, bloating, and bloody ascites as manifestations. The diagnosis was confirmed by cytology of ascites aspiration fluid and further verified by laparoscopic exploratory biopsy. The characteristics of signs and clinical manifestations in this case are less common. As everyone knows, asbestos exposure is usually associated with pleural mesothelioma, but only 6%-10% of malignant mesothelioma cases originate from the peritoneum, which is far less than pleural mesothelioma. Generally, its non-specificity provides a huge challenge to medical professionals in its diagnosis, and this is also the main reason for delayed diagnosis. Patients should be vigilant, even though no clear risk factor is observed.

Usefulness of NF2 hemizygous loss detected by fluorescence in situ hybridization in diagnosing pleural mesothelioma in tissue and cytology material: A multi-institutional study

OBJECTIVES

BAP1, CDKN2A, and NF2 are the most frequently altered genes in pleural mesotheliomas (PM). Discriminating PM from benign mesothelial proliferation (BMP) is sometimes challenging; it is well established that BAP1 loss, determined by immunohistochemistry (IHC), and CDKN2A homozygous deletion (HD), determined by fluorescence in situ hybridization (FISH), are useful. However, data regarding the diagnostic utility of NF2 FISH in PM is limited. Thus, we performed a multi-institutional study examining the utility of NF2 alterations determined by FISH for diagnosing PM in combination with BAP1 loss and CDKN2A HD.

MATERIALS AND METHODS

Multi-institutional PM cases, including 106 surgical and 107 cell block samples as well as 37 tissue cases of benign mesothelial proliferation (BMP) and 31 cell block cases with reactive mesothelial cells (RMC), were collected and analyzed using IHC for BAP1 and FISH for CDKN2A and NF2.

RESULTS

In PM, NF2 FISH revealed hemizygous loss (HL) in 54.7% of tissue cases (TC) and 49.5% of cell block cases (CBC), with about 90% of HL being monosomy. CDKN2A HD or BAP1 loss were detected in 75.5%/65.4% TC or 63.6%/60% CBC, respectively. BMP or RMC showed no BAP1 loss, CDKN2A HD, or NF2 HL. For discriminating PM from BMP, a combination of BAP1 loss, CDKN2A HD, and NF2 HL yielded enhanced sensitivity of 98.1% TC/94.4% CBC. BAP1 loss, CDKN2A HD, or NF2 HL were observed in 69%, 70%, or 58% of epithelioid PM, but in 9%, 91%, or 27% of sarcomatoid PM, respectively. Histotype, histological gradings, and CDKN2A deletion status showed significant differences in overall survival, while BAP1 loss and NF2 HL did not.

CONCLUSION

NF2 HL, consisting predominantly of monosomy, can be detected by FISH in both TC and CBC of PM, and is effective for distinguishing PM from BMP, especially when combined with BAP1 loss and CDKN2A HD.

Multimodal therapy of epithelioid pleural mesothelioma: improved survival by changing the surgical treatment approach

Background

The exact role and type of surgery for malignant pleural mesothelioma (MPM) remains controversial. This study aimed at analyzing a 20-year single center perioperative experience in MPM surgery at our high-volume thoracic surgery center and comparing the overall survival after trimodal extrapleural pneumonectomy (EPP) and extended pleurectomy and decortication combined with hyperthermic intrathoracic chemoperfusion (EPD/HITOC) and adjuvant chemotherapy with that after chemotherapy (CTx) alone.

Methods

Patients with epithelioid MPM treated with neoadjuvant chemotherapy, EPP and adjuvant radiotherapy within a trimodal concept or EPD/HITOC in combination with adjuvant chemotherapy between 2001 and 2018 were included in this retrospective analysis. Surgical cohorts were compared to patients treated with standard chemotherapy.

Results

Overall, 182 patients (69 EPP, 57 EPD/HITOC, 56 CTx) were analyzed. Due to occupational exposure to asbestos for most of the patients, 154 patients (84.6%) were male. The patients in the surgical cohorts were significantly younger than those in the CTx cohort. There was no significant difference between the proportion of patient age and side. The median overall survival of the EPD/HITOC cohort with 38.1 months was significantly longer than that of the EPP and CTx cohorts (24.0 and 15.8 months). Better survival was significantly associated with an ECOG 0 performance status, age below 70 years, and negative lymph node status. In the multivariate analysis, EPD/HITOC was significantly associated with improved overall survival. Perioperative morbidity was lower in the EPD/HITOC group than in the EPP cohort.

Conclusions

EPD/HITOC is feasible and safe for localized epithelioid pleural mesothelioma. Changing the surgical approach to a less radical lung-sparing technique may improve overall survival compared to trimodal EPP.

[Pleural deciduoid mesothelioma: A report of 3 cases and a review of the literature]

Deciduoid mesothelioma is an uncommon histological variant of epithelial mesothelioma which is extremely clinically aggressive. We report 3 cases of pleural caducoid mesothelioma in women of 75, 74 and 23 years of age. All patients presented with dyspnoea, vomiting and pelvic pain. Their imaging studies showed nodular pleuropericardic thickening, a parietal pleuropericardic solid mass and a large thoracic mass, respectively. Only one of them could be treated with chemotherapy, surgery and radiotherapy. Post diagnostic survival was 24 days, 1 month and 17 months respectively (mean 6.2 months). We describe the clinicopathological and immunohistochemical findings together with a review of the relevant literature.

Training and validation of a knowledge-based dose-volume histogram predictive model in the optimisation of intensity-modulated proton and volumetric modulated arc photon plans for pleural mesothelioma patients

BACKGROUND

To investigate the performance of a narrow-scope knowledge-based RapidPlan (RP) model for optimisation of intensity-modulated proton therapy (IMPT) and volumetric modulated arc therapy (VMAT) plans applied to patients with pleural mesothelioma. Second, estimate the potential benefit of IMPT versus VMAT for this class of patients.

METHODS

A cohort of 82 patients was retrospectively selected; 60 were used to "train" a dose-volume histogram predictive model; the remaining 22 provided independent validation. The performance of the RP models was benchmarked, comparing predicted versus achieved mean and near-to-maximum dose for all organs at risk (OARs) in the training set and by quantitative assessment of some dose-volume metrics in the comparison of the validation RP-based data versus the manually optimised training datasets. Treatment plans were designed for a prescription dose of 44 Gy in 22 fractions (proton doses account for a fixed relative biological effectiveness RBE = 1.1).

RESULTS

Training and validation RP-based plans resulted dosimetrically similar for both VMAT and IMPT groups, and the clinical planning aims were met for all structures. The IMPT plans outperformed the VMAT ones for all OARs for the contra-lateral and the mean and low dose regions for the ipsilateral OARs. Concerning the prediction performance of the RP models, the linear regression for the near-to-maximum dose resulted in D_achieved = 1.03D_predicted + 0.58 and D_achieved = 1.02D_predicted + 1.46 for VMAT and IMPT, respectively. For the mean dose it resulted: D_achieved = 0.99D_predicted + 0.34 and D_achieved = 1.05D_predicted + 0.27 respectively. In both cases, the linear correlation between prediction and achievement is granted with an angular coefficient deviating from unity for less than 5%. Concerning the dosimetric comparison between manual plans in the training cohort and RP-based plans in the validation cohort, no clinical differences were observed for the target volumes in both the VMAT and IMPT groups. Similar consistency was observed for the dose-volume metrics analysed for the OAR. This proves the possibility of achieving the same quality of plans with manual procedures (the training set) or with automated RP-based methods (the validation set).

CONCLUSION

Two models were trained and validated for VMAT and IMPT plans for pleural mesothelioma. The RP model performance resulted satisfactory as measured by the agreement between predicted and achieved (after full optimisation) dose-volume metrics. The IMPT plans outperformed the VMAT plans for all the OARs (with different intensities for contra- or ipsilateral structures). RP-based planning enabled the automation of part of the optimisation and the harmonisation of the dose-volume results between training and validation. The IMPT data showed a systematic significant dosimetric advantage over VMAT. In general, using an RP-based approach can simplify the optimisation workflow in these complex treatment indications without impacting the quality of plans.

Immunotherapy combined with antiangiogenic agents in patients with advanced malignant pleural mesothelioma: A case report

BACKGROUND

Malignant pleural mesothelioma has limited therapeutic options and a poor outcome. Antiangiogenic agents might increase the efficacy of immunotherapy as second-line treatment of advanced-stage malignancies.

CASE SUMMARY

A patient with stage IIIB pleural mesothelioma received second-line treatment with a combination of pembrolizumab, bevacizumab and chemotherapy following standard chemotherapy under the guidance of second-generation sequencing. He achieved a partial response after four cycles of treatment with progression-free survival of 5 mo. Pembrolizumab was suspended due to grade 2 immunerelated pneumonia, which was resolved by oral glucocorticoids. However, disease progression was observed after immunotherapy rechallenge and anlotinib therapy. The patient had disease progression, multiorgan dysfuntion and died suddenly in October 2019.

CONCLUSION

The combination of immune checkpoint inhibitor, anti-angiogenic agents and chemotherapy showed effective response for advanced pleural mesothelioma, but with adverse reactions.

Pleural mesothelioma risk by industry and occupation: results from the Multicentre Italian Study on the Etiology of Mesothelioma (MISEM)

BACKGROUND

The Italian mesothelioma registry (ReNaM) estimates mesothelioma incidence and addresses its etiology by assessing cases' exposures but cannot provide relative risk estimates.

OBJECTIVES

i) To estimate pleural mesothelioma relative risk by industry and occupation and by ReNaM categories of asbestos exposure; and ii) to provide quantitative estimates of the exposure-response relationship.

METHODS

A population-based mesothelioma case-control study was conducted in 2012-2014 in five Italian regions. Cases and age and gender frequency-matched controls were interviewed using a standard ReNaM questionnaire. Experts coded work histories according to international standard classifications of industries/occupations and assigned asbestos exposure according to ReNaM categories. Job codes were further linked to SYN-JEM, a quantitative job-exposure matrix. Cumulative exposure (CE, f/mL-years) was computed by summing individual exposures over lifetime work history. Unconditional logistic regression analyses adjusted by gender, centre and age were fitted to calculate odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Among men we observed increased risks of mesothelioma in many industries and associated occupations, including: asbestos-cement (OR = 3.43), manufacture of railroad equipment (OR = 8.07), shipbuilding and repairing (OR = 2.34), iron and steel mills (OR = 2.15), and construction (OR = 1.94). ORs by ReNaM exposure categories were as follows: definite/probable occupational exposure (OR = 15.8, men; OR = 8.80, women), possible occupational (OR = 2.82, men; OR = 3.70, women), sharing home with an exposed worker (OR = 2.55, men; OR = 10.3, women), residential (OR = 2.14, men; OR = 3.24, women). Based on SYN-JEM, mesothelioma risk increased by almost 30% per f/mL-year (OR = 1.28, CI 1.16-1.42).

CONCLUSIONS

Out study involved five regions with historically different types and levels of industrial development, encompassing one third of the Italian population and half of Italian mesothelioma cases. As expected, we found increased pleural mesothelioma risk in the asbestos industry and in trades with large consumption of asbestos materials. Clear associations were found using both qualitative (ReNaM classifications) and quantitative estimates (using SYN-JEM) of past asbestos exposure, with clear evidence of an exposure-response relationship.

DNA methylation-based machine learning classification distinguishes pleural mesothelioma from chronic pleuritis, pleural carcinosis, and pleomorphic lung carcinomas

OBJECTIVES

Our goal was to evaluate the diagnostic value of DNA methylation analysis in combination with machine learning to differentiate pleural mesothelioma (PM) from important histopathological mimics.

MATERIAL AND METHODS

DNA methylation data of PM, lung adenocarcinomas, lung squamous cell carcinomas and chronic pleuritis was used to train a random forest as well as a support vector machine. These classifiers were validated using an independent validation cohort including pleural carcinosis and pleomorphic variants of lung adeno- and squamous cell carcinomas. Furthermore, we performed differential methylation analysis and used a deconvolution method to estimate the composition of the tumor microenvironment.

RESULTS

T-distributed stochastic neighbor embedding clearly separated PM from lung adenocarcinomas and squamous cell carcinomas, but there was a considerable overlap between chronic pleuritis specimens and PM with low tumor cell content. In a nested cross validation on the training cohort, both machine learning algorithms achieved the same accuracies (94.8%). On the validation cohort, we observed high accuracies for the support vector machine (97.8%) while the random forest performed considerably worse (89.5%), especially in distinguishing PM from chronic pleuritis. Differential methylation analysis revealed promoter hypermethylation in PM specimens, including the tumor suppressor genes BCL11B, EBF1, FOXA1, and WNK2. Deconvolution of the stromal and immune cell composition revealed higher rates of regulatory T-cells and endothelial cells in tumor specimens and a heterogenous inflammation including macrophages, B-cells and natural killer cells in chronic pleuritis.

CONCLUSION

DNA methylation in combination with machine learning classifiers is a promising tool to reliably differentiate PM from chronic pleuritis and lung cancer, including pleomorphic carcinomas. Furthermore, our study highlights new candidate genes for PM carcinogenesis and shows that deconvolution of DNA methylation data can provide reasonable insights into the composition of the tumor microenvironment.

A necropsy-based study of 185 cases

INTRODUCTION

Malignant pleural mesothelioma (MPM) is an asbestos-related disease with poor survival. The prognostic role of histological subtype is well established. Some studies (without a biological hypothesis) suggested that higher asbestos lung burden is associated with reduced survival.

OBJECTIVES

We performed a necropsy-based study of MPM patients to analyze the relationship between asbestos lung burden and survival.

METHODS

We selected subjects from two series of necropsies: residents in Brescia province (North-West Italy) and workers (or persons living with them) employed in the Monfalcone shipyards (North-East Italy). Asbestos fibers (AF) and bodies (AB) in lung samples were counted using a scanning electron and an optical microscope respectively. Separately in the two series, we analyzed median survival time and fitted multivariable Cox regression models (adjusted for gender, period and age at diagnosis, and morphology) to calculate hazard ratios (HR) and 95% confidence intervals (CI) for three levels of AF counts (reference: <1 million fibers per gram of dry lung tissue).

RESULTS

We analyzed 185 necropsies, 83 in Brescia and 102 in Monfalcone. Despite a much higher lung burden in Monfalcone patients, median survival was slightly shorter in Brescia (8.3 months) than in Monfalcone (10.2 months). In Brescia, for medium (1-9.9) and high (10+) fiber burden HRs were 0.91 (95% CI 0.54-1.53) and 1.23 (95% CI 0.41-3.70). In Monfalcone, the corresponding HRs were 1.18 (95% CI 0.59-2.35) and 1.63 (95% CI 0.77-3.45).

CONCLUSION

No relationship between asbestos lung burden and survival was found. Histological subtype was the strongest prognostic determinant.

Two-year intermittent exposure of a multiwalled carbon nanotube by intratracheal instillation induces lung tumors and pleural mesotheliomas in F344 rats

BACKGROUND

A mounting number of studies have been documenting the carcinogenic potential of multiwalled carbon nanotubes (MWCNTs); however, only a few studies have evaluated the pulmonary carcinogenicity of MWCNTs in vivo. A 2-year inhalation study demonstrated that MWNT-7, a widely used MWCNT, was a pulmonary carcinogen in rats. In another 2-year study, rats administered MWNT-7 by intratracheal instillation at the beginning of the experimental period developed pleural mesotheliomas but not lung tumors. To obtain data more comparable with rats exposed to MWNT-7 by inhalation, we administered MWNT-7 to F344 rats by intratracheal instillation once every 4-weeks over the course of 2 years at 0, 0.125, and 0.5 mg/kg body weight, allowing lung burdens of MWNT-7 to increase over the entire experimental period, similar to the inhalation study.

RESULTS

Absolute and relative lung weights were significantly elevated in both MWNT-7-treated groups. Dose- and time-dependent toxic effects in the lung and pleura, such as inflammatory, fibrotic, and hyperplastic lesions, were found in both treated groups. The incidences of lung carcinomas, lung adenomas, and pleural mesotheliomas were significantly increased in the high-dose group compared with the control group. The pleural mesotheliomas developed mainly at the mediastinum. No MWNT-7-related neoplastic lesions were noted in the other organs. Cytological and biochemical parameters of the bronchoalveolar lavage fluid (BALF) were elevated in both treated groups. The lung burden of MWNT-7 was dose- and time-dependent, and at the terminal necropsy, the average value was 0.9 and 3.6 mg/lung in the low-dose and high-dose groups, respectively. The number of fibers in the pleural cavity was also dose- and time-dependent.

CONCLUSIONS

Repeated administration of MWNT-7 by intratracheal instillation over the 2 years indicates that MWNT-7 is carcinogenic to both the lung and pleura of rats, which differs from the results of the 2 carcinogenicity tests by inhalation or intratracheal instillation.

Long-term outcomes after lung-sparing surgery for epithelial mesothelioma

Background

This observational study evaluates retrospectively the long-term outcomes after pleurectomy/decortication for pleural mesothelioma, with and without the resection/reconstruction of diaphragm and pericardium.

Methods

Data from 155 consecutive patients undergoing lung-sparing surgery for epithelial pleural mesothelioma were reviewed. Selection criteria for surgery were cT1-3, cN0-1, good performance status, age <80 years. Perioperative Pemetrexed-Platinum regimen was administered as induction in 101 cases (65.2%) and as adjuvant treatment in 54 cases (34.8%). Extended pleurectomy/decortication was performed in 87 cases (56.12%). In 68 patients (43.87%) standard pleurectomy/decortication was performed without resection/reconstruction of diaphragm and pericardium, when tumour infiltration was deemed absent after intraoperative frozen section. The log-rank test and Cox regression model were used to assess the factors affecting overall survival and recurrence free survival.

Results

Median follow-up was 20 months. The 2- and 5-year survival rate was 60.9% and 29.2% with a median survival of 34 months. An improved survival was observed when standard pleurectomy/decortication was carried out (P=0.007). A significant impact on survival was found comparing the TNM-stages (P=0.001), pT (P=0.002) and pN variables (P=0.001). Multivariate analysis identified the pN-status (P=0.003) and standard pleurectomy/decortication (P=0.017) as predictive for longer survival. The recurrence-free survival >12 months was strongly related to the overall survival (P<0.001). The macroscopic complete resection (P=0.001), TNM-stage (P=0.003) and pT-status (P=0.001) are related to relapse.

Conclusions

Within multimodal management of pleural mesothelioma, lung-sparing surgery is a valid option even with more conservative technique. A benefit for a longer survival was observed in the early stage of disease, with pN0 and when pleurectomy/decortication is carried out, preserving diaphragm and pericardium. Recurrence is not affected by the type of surgery, and a recurrence-free interval >12 months is predictive of an increased survival when the macroscopic complete resection is achieved.

Histology of the pleural rind at [18F]FDG PET/CT hot and cold spots in mesothelioma patients after talc pleurodesis and neoadjuvant chemotherapy

The role of 2-deoxy-2-[¹⁸F]fluoro-D-glucose positron emission tomography/computed tomography ([¹⁸F]FDG PET/CT) in evaluating induction chemotherapy in pleural mesothelioma (PM) patients is debated. We compared histology at tumor sites with high versus low [¹⁸F]FDG uptake in order to define a morphologic correlate for persistent metabolic activity. Twenty PM patients with talc pleurodesis and induction chemotherapy followed by extrapleural pleuro-pneumonectomy (EPP, n = 17) or tumor debulking (n = 3) were included. All patients received a PET/CT scan prior to surgery. Orthogonal tissue sections of pleural rind (n total=86) were taken at areas of maximum standardized uptake value (SUV_max, n = 53) and of low [¹⁸F]FDG uptake (n = 33) and scored on hematoxylin-eosin and immunohistochemical stainings. Total metabolic activity was scored semiquantitatively. Mean SUV_max of hot and cold spots correlated with total metabolic activity per patient, but no correlation was found with ypT and tumor cells were present in both hot and cold areas. SUV_max of only hot spots and cold versus hot spots as well as cold versus hot patients correlated with increased thickness of total pleural rind and fibrosis reaction, but not thickness of vital tumor cells or giant cell reaction. They further correlated with increased expression of glucose transporter 1 (GLUT1) in giant cells but not mesothelioma amount, density, vitality or vascularization. Biphasic histology was associated with SUV_max in only hot spots and higher total metabolic activity (all p-values <0.05). Interpretation of [¹⁸F]FDG PET/CT in PM patients is difficult after talc pleurodesis and induction chemotherapy. High glucose turnover is mostly related to fibro-inflammatory remodeling of the pleural rind and GLUT1 transporter expression in giant cells. Response assessment using this technology should only be done to assess extra-thoracic lesions.

Cytoreductive Thoracic Surgery Combined with Hyperthermic Chemoperfusion for Pleural Malignancies: A Single-Center Experience

BACKGROUND

Lung-sparing cytoreductive surgery by extended pleurectomy and decortication (EPD) in combination with hyperthermic intrathoracic chemoperfusion (HITOC) forms a promising treatment strategy for malignant pleural mesothelioma and recurrent pleural thymic malignancies.

OBJECTIVES

The objective of this study was to scrutinize the surgical procedure and perioperative patient management with emphasis on perioperative morbidity and local tumor control.

METHODS

In 2014, a standardized EPD and HITOC procedure was implemented at the Thoraxklinik Heidelberg. This retrospective analysis included clinical data of consecutive patients with pleural mesothelioma and pleural metastasized malignancies treated by EPD and HITOC. The surgical procedure, perioperative management, lung function data, and progression-free survival (PFS) were analyzed.

RESULTS

In the time range between April 2, 2014 and July 2018, 76 patients with pleural malignancies have been treated with EPD and HITOC, and were analyzed retrospectively. It included 61 patients with pleural mesothelioma and 15 patients with pleural metastases of thymic malignancies (12), non-small cell lung cancer (1), colorectal carcinoma (1), and sarcoma (1). Perioperative morbidity following EPD and HITOC treatments represented 23.7% of overall malignancies, while 30- and 90-day mortality were 0 and 1.3%, respectively. Median PFS lasted 18.4 months for mesothelioma and 72.2 months for thymic malignancies.

CONCLUSION

Combining EPD with HITOC can be performed in patients with either pleural mesothelioma or pleural metastases resulting in low perioperative morbidity and mortality as well as remarkable local tumor control.

Primary Pericardial Mesothelioma: A Population-Based Propensity Score-Matched Analysis

Primary pericardial mesothelioma is a rare malignancy of the mesothelial lining of the pericardium. This study aimed to evaluate the clinical characteristics and survival outcomes of these patients using a United States population-based cancer database. We queried the Surveillance, Epidemiology, and End Results program (1973-2015). Primary pericardial mesothelioma patients with complete follow-up data were included, and primary pleural mesothelioma patients were identified as controls. Propensity-score matching was used to balance individual characteristics. Kaplan-Meier analysis and log-rank tests were performed to compare overall survival. Forty-one primary pericardial mesothelioma and 15,970 primary pleural mesothelioma patients were identified. Before matching, when compared to the pleural mesothelioma counterparts, primary pericardial mesothelioma patients were younger (median 57 vs 73 years, P < 0.001), more likely to be female (46.3% vs 20.2%, P < 0.001), more likely to be nonwhite (24.4% vs 8.4%, P = 0.001), and less likely to have been diagnosed in the most recent study decade (2006-2015, 34.1% vs 43.5%, P = 0.002). The overall 1- and 2-year survival rates were 22.0% and 12.2%, with a median survival of 2 months (IQR: 1-6). After 1:2 nearest neighbor propensity-score matching, 38 pericardial mesothelioma and 76 matched pleural mesothelioma cases were identified. The 2 matched groups had comparable baseline characteristics, including age, sex, race, year of diagnosis, histological type, and cancer history. Compared to their pleural mesothelioma counterparts, primary pericardial mesothelioma patients were less likely to receive chemotherapy (23.7% vs 50.0%, P = 0.01) and had worse overall survival (median survival: 2 vs 10 months, log-rank P = 0.006). Primary pericardial mesothelioma has worse survival outcomes than pleural mesothelioma, with a median survival of only 2 months. These patients should seek care from experienced multidisciplinary teams at tertiary care centers that handle high volumes of mesothelioma patients.

A short report

Introduction

Diffuse malignant peritoneal mesothelioma (DMPM) is a rare malignant neoplasm with poor survival that shares some similarities with the best-known pleural variant, pleural mesothelioma. The recent European Reference Network on Rare Adult Cancers (EURACAN)/International Association for the Study of Lung Cancer (IASLC) proposals attempted to improve the histological diagnosis and patient risk stratification. Herein, we investigated whether the pathology recommendations and suggestions of the pleural proposals were applicable to diffuse malignant peritoneal mesothelioma.

Methods

Fifty multiple laparoscopic biopsies of DMPM were consecutively collected at the Pathology Unit of the University of Bari. A two-tier system, i.e., low, and high grade, was used to categorize 34 epithelioid DMPMs. Architectural patterns, cytological features and stromal changes were also reported. Immunohistochemistry was performed for BRCA1-associated protein 1 (BAP1), programmed death-ligand 1 (PD-L1), and Ki67, while fluorescence in situ hybridization (FISH) was performed for p16/cyclin-dependent kinase inhibitor 2A (CDKN2A).

Results

High-grade epithelioid mesothelioma, high Ki67, and p16/CDKN2A deletion were significantly associated with short survival (p = 0.004, p < 0.0001, and p = 0.002, respectively). BAP1 loss and PD-L1 negativity were the most common findings. Multivariate analysis revealed that the nuclear grading system and p16 deletion significantly correlated with survival (p = 0.003 each).

Conclusions

The present study examined the prognostic significance of several factors proposed for pleural mesothelioma in an extra pleural site. Notably, the introduction of a grading system may provide better risk stratification in epithelioid DMPM. Ki67, BAP1 and p16/CDKN2A should also be measured whenever possible. A detailed report with all supportive data would allow us to collect sufficient information for use in further studies on larger case series.

Reconstruction of asbestos exposure in workers suffering from pleural neoplasms and employed in sectors not generally associated with high exposure levels: the importance of an accurate standardized assessment of occupational medicine

Introduction

Malignant pleural mesothelioma onset in workers exposed to asbestos is well known with reference to multiple working sectors. In some cases, occurring among workers of sectors characterized by a presumed lower relevance of asbestos exposure, the absence of a well-defined correlation can prevent their emergence and compensation. To improve definition of these cases, this article underlines the importance of a standardized approach to occupational anamnesis.

Methods

Thorough standardized occupational health assessment method application in a case of pleural malignant neoplasm occurred in a hauler, a job generally not associated with high levels of exposure to asbestos fibres.

Results

Assessment of malignant pleural mesothelioma diagnosis and dual mode relevant occupational exposure to asbestos during both truck driving and loading and unloading operations of asbestos-containing goods.

Conclusions

Systematic occupational medicine assessment with accurate standardized approach is essential for reconstruction of asbestos exposure, in order to highlight every aspect useful to establish causal link between cases of pleural mesothelioma and possible occupational and non-occupational exposure to the mineral, even in cases where the first-level occupational history does not appear to be suggestive.

Accuracy of pleural biopsy for the diagnosis of histologic subtype of malignant pleural mesothelioma: Necropsy-based study of 134 cases

BACKGROUND

Definition of histologic subtype of malignant pleural mesothelioma (MPM) is important for management of patients, because surgical treatment improves prognosis for patients with epithelioid but not biphasic or sarcomatoid MPM. In a series of necropsies performed in a hospital specialized for MPM diagnosis, we retrospectively investigated the accuracy of histologic diagnosis performed on pathologic specimens collected through pleural biopsies obtained at video-assisted thoracoscopic surgery (VATS) or surgery.

METHODS

We reviewed histologic records of an unselected series of autopsies performed in patients with MPM employed in the Monfalcone shipyards (Northeast Italy) or living with shipyard workers from 1999 through 2017. Using necropsy results as a gold standard, we calculated sensitivity, specificity, and positive and negative predictive values of histology from VATS or surgery after combining nonepithelioid subtypes.

RESULTS

We retrieved necropsy records for 134 patients: 62 (46.3%) with epithelioid, 51 (38.1%) with biphasic, and 21 (15.7%) with sarcomatoid MPM. We observed good sensitivity of VATS (0.94) and surgery (0.89) in diagnosing epithelioid MPM. Conversely, specificity was low (VATS: 0.46; surgery: 0.32). Therefore, positive predictive values were also low (VATS: 0.58; surgery: 0.60). Misclassification was particularly high for biphasic MPM (three-fourths of biphasic MPM at necropsy had been classified as epithelioid at VATS or surgery).

CONCLUSIONS

We observed a substantial degree of misclassification between epithelioid and biphasic MPM for pleural biopsies performed during VATS. Our results suggest caution should be taken in using histologic subtype obtained from VATS in selecting patients with MPM for surgical treatment. We also observed substantial misclassification of biospecimens collected during MPM surgery.

A quantitative weight of evidence assessment of Hill's guidelines for causal inference for cosmetic talc as a cause of mesothelioma

Cosmetic talc has been suggested to cause mesothelioma. To assess a potential causal relationship between cosmetic talc and mesothelioma, a quantitative weight of evidence analysis was performed in accordance with Hill's nine original guidelines for causal inference using a published empirical model to weight each respective guideline. Various epidemiological, toxicological, and exposure studies related to cosmetic talc and risk of mesothelioma were included in an evaluation of each of Hill's guidelines. Probabilities that the guidelines were true were assigned based on expert judgment. We applied a sensitivity analysis to evaluate the variability of our probability estimates. The overall probability of causality for cosmetic talc and mesothelioma was approximately 1.29% (range: 0.73%-3.96%). This low probability of causality supports the conclusion that cosmetic talc is not related to the development of mesothelioma.

Radiological evaluation of malignant pleural mesothelioma - defining distant metastatic disease

BACKGROUND

Malignant pleural mesothelioma (MPM) is traditionally characterized by local destructive spread of the pleura and surrounding tissues. Patient outcomes in MPM with distant metastatic dissemination are lacking.

METHODS

In this retrospective study, we reviewed a cohort of 164 MPM patients referred to a Phase I trials unit, aiming to describe identified metastatic sites, and correlate with clinical outcomes.

RESULTS

67% of patients were diagnosed with distant metastatic disease with a high incidence of bone (19%), visceral (14%), contralateral lung (35%) and peritoneal metastases (22%). Peritoneal metastases were more likely in epithelioid versus biphasic/ sarcomatoid MPM (p = 0.015). Overall survival was 23.8 months with no statistical difference in survival between those with distant metastases and those without.

CONCLUSIONS

This report highlights the frequency of distant metastases and encourages further radiological investigations in the presence of symptoms. In particular, given the relatively high incidence of bone metastases, bone imaging should be considered in advanced MPM clinical workflow and trial protocols. The presence of distant metastases does not appear to have prognostic implications under existing treatment paradigms. This cohort of MPM patients gives an indication of patterns of metastatic spread that are likely to become prevalent as prognosis improves with emerging treatment paradigms.

The Staging of Malignant Pleural Mesothelioma

Staging of malignant pleural mesothelioma has been challenging because of a paucity of cases and poor survival. At least 5 staging systems were proposed before 1990 until the first consensus system was published in 1995. This system used tumor, node, metastasis designations and borrowed heavily from parenchymal lung cancer descriptors. With the establishment of a database to collect cases from 1995 to 2013, evidence-based revisions to the 1995 staging classification were published in 2016. With improving imaging technology, clinical staging will become more refined and, it is hoped, more useful for prognostication even without operative resection.

Frequent expression of conventional endothelial markers in pleural mesothelioma: usefulness of claudin-5 as well as combined traditional markers to distinguish mesothelioma from angiosarcoma

OBJECTIVES

Distinguishing pleural sarcomatoid mesotheliomas from true sarcomas is challenging because the former does not always express the mesothelial markers, and diagnosis is often made on the basis of keratin expression. Consequently, sarcomas such as angiosarcomas that express keratin complicate the differential diagnosis. Furthermore, some mesotheliomas have been reported to express endothelial markers. The aim of this study is to identify useful markers for distinguishing pleural sarcomatoid mesothelioma from angiosarcoma.

MATERIALS AND METHODS

This study enrolled 147 patients with pleural mesothelioma-93 with epithelioid, 25 with biphasic, and 29 with sarcomatoid subtypes-and 41 patients with angiosarcomas in various organs. The expression levels of cytokeratin, mesothelial, and endothelial markers were assayed in both groups to identify the markers that could assist in distinguishing mesothelioma from angiosarcoma. Cytokeratin (AE1/AE3, CAM 5.2), endothelial (CD31, CD34, ERG, factor VIII, and claudin-5), and mesothelial (calretinin, WT-1, podoplanin (D2-40), EMA, and CK5/6) markers were immunohistochemically assayed using tissue blocks.

RESULTS

More than 90% of the mesotheliomas and less than 20% of the angiosarcomas expressed cytokeratin. Calretinin was expressed in 82% of all types of mesotheliomas but in only 48% of sarcomatoid mesotheliomas. Endothelial markers were expressed in mesothelioma tissues-CD31 in 10.3%, CD34 in 3.5%, ERG in 29%, and factor VIII in 3.4%-and the positivity was higher in sarcomatoid than in epithelioid and biphasic mesotheliomas. Claudin-5 was expressed in all the angiosarcomas, but not in any of the mesotheliomas.

CONCLUSION

We found overlapping immunophenotypes in pleural mesotheliomas and angiosarcomas, but the sensitivity and specificity of claudin-5 expression were sufficient to distinguish between them. The differential diagnosis of mesothelioma should therefore include claudin-5 in a panel of immunohistochemical markers to distinguish mesothelioma from angiosarcoma.

Ovarian metastasis from malignant pleural mesothelioma

BACKGROUND

Malignant pleural mesothelioma (MPM) is a rare and aggressive disease of the pleura with a dismal prognosis. Distant metastases most commonly occur in the liver, spleen, and thyroid gland. To our knowledge, ovarian metastases have never been described.

CASE DESCRIPTION

We describe a case of a woman with recurrent malignant pleural mesothelioma presenting a single ovarian metastasis, surgically resected.

CONCLUSIONS

This case report highlights the importance of using a complete staging protocol in patients with MPM to improve patient management. A whole-body computed tomography (CT) scan with contrast enhancement and possibly positron emission tomography-CT should be performed to identify any distant metastases before deciding on treatment strategy.

A Phase II Study of Pazopanib in Patients with Malignant Pleural Mesothelioma: NCCTG N0623 (Alliance)

PURPOSE

Preclinical and clinical data have shown promise in using antiangiogenic agents to treat malignant pleural mesothelioma (MPM). We conducted this phase II study to evaluate the efficacy and toxicity of single-agent pazopanib in patients with MPM.

MATERIALS AND METHODS

Patients with MPM who had received 0-1 prior chemotherapy regimens were eligible to receive pazopanib at a dose of 800 mg daily. The primary endpoint was progression-free survival rate at 6 months (PFS6), with a preplanned interim analysis for futility. Secondary endpoints included overall survival (OS), PFS, adverse events assessment and clinical benefit (complete response, partial response [PR], and stable disease [SD]).

RESULTS

Thirty-four evaluable patients were enrolled, with a median age of 73 years (49-84). The trial was closed early because of lack of efficacy at the preplanned interim analysis. Only 8 patients (28.6%; 95% confidence interval [CI], 13.2-48.7%) in the first 28 evaluable were progression-free at 6 months. PFS6 was 32.4% (95% CI, 17.4-50.5). There were 2 PR (5.9%) and 16 SD (47.1%). The overall median PFS and OS were 4.2 months (95% CI, 2.0-6.0) and 11.5 months (95% CI: 5.3-18.2), respectively. The median PFS and OS for the previously untreated patients was 5.4 months (95% CI, 2.7-8.5) and 16.6 months (95% CI, 6.6-30.6), respectively; and 2.0 months (95% CI, 1.3-4.2) and 5.0 months (95% CI: 3.0-11.9), respectively, for the previously treated patients. Grade 3 or higher adverse events were observed in 23 patients (67.6%).

CONCLUSION

Single-agent pazopanib was poorly tolerated in patients with MPM. The primary endpoint of PFS6 was not achieved in the current study. ClinicalTrials.gov identification number. NCT00459862.

IMPLICATIONS FOR PRACTICE

Single-agent pazopanib did not meet its endpoint in this phase II trial in malignant mesothelioma. Pazopanib is well tolerated in mesothelioma patients with a manageable toxicity profile. There is a need to better identify signals of angiogenesis that can be targeted in mesothelioma. Encouraging findings in frontline treatment warrant further investigations in combination with chemotherapy or immunotherapy.

Surgery for pleural mesothelioma, when it is indicated and why: arguments against surgery for malignant pleural mesothelioma

Extrapleural pneumonectomy (EPP) and pleurectomy decortication (PD) are radical operations for malignant pleural mesothelioma (MPM) that remain controversial among thoracic surgeons. There is a lack of randomized evidence to support a survival benefit when major surgical resection is included in multi-modality treatment regimens. Current data from retrospective single institution reviews and prospective trials such as the Surgery for Mesothelioma After Radiation Therapy (SMART) trial are limited by biased patient selection to include only the healthiest patients with most limited disease burden. This patient population predictably has relatively longer survival times than patients with inoperable advanced disease. The only randomized trial to date that has objectively evaluated the true benefit of surgical resection was the Mesothelioma and Radical Surgery (MARS) trial which actually showed shorter survival times among patients who underwent EPP compared with those treated medically. Critics of the MARS trial cite a high perioperative mortality rate for driving these results, however a similar trial has never been repeated to refute the MARS trial results. Finally, it is relevant to consider the high mortality and morbidity rates associated with major operations when recommending these interventions to MPM patients. There is a growing body of literature that identifies patients who clearly obtain no benefit from surgery including those with sarcomatoid or biphasic histology, nodal disease, elevated CRP, elevated platelets and advanced age. Surgery in MPM has risks and is of questionable benefit with outcomes data biased by patient selection of those who will have longer overall survival times regardless of treatment.

Gender differences in pleural mesothelioma occurrence in Lombardy and Piedmont, Italy

BACKGROUND

Higher mesothelioma rates in men (vs women) reflect more frequent and more intense asbestos exposure. We assessed the impact of exposure difference between genders on age-specific rates of pleural mesothelioma (PM) occurrence using data from two Italian regions.

METHODS

We used data from the Lombardy and Piedmont mesothelioma registries (period 2000-2016, age 45-74 years) to compare rates of PM in men and women and to estimate the rate advancement period (RAP).

RESULTS

Based on 3384 cases (2405 men, 979 women) in Lombardy and 2042 (1389 men, 653 women) in Piedmont, the rate ratio was 2.81 (90% confidence interval: 2.61-3.03) in Lombardy and 2.39 (2.17-2.62) in Piedmont. In both regions RAP ranged from 7 to 10 years (at age 45 and 63 in men, respectively).

CONCLUSION

Men showed more than twofold increased PM rates and reached the same incidence as women 7-10 years earlier. RAP can be a useful measure of exposure impact on premature disease occurrence.

Redefining malignant pleural mesothelioma types as a continuum uncovers immune-vascular interactions

BACKGROUND

Malignant Pleural Mesothelioma (MPM) is an aggressive disease related to asbestos exposure, with no effective therapeutic options.

METHODS

We undertook unsupervised analyses of RNA-sequencing data of 284 MPMs, with no assumption of discreteness. Using immunohistochemistry, we performed an orthogonal validation on a subset of 103 samples and a biological replication in an independent series of 77 samples.

FINDINGS

A continuum of molecular profiles explained the prognosis of the disease better than any discrete model. The immune and vascular pathways were the major sources of molecular variation, with strong differences in the expression of immune checkpoints and pro-angiogenic genes; the extrema of this continuum had specific molecular profiles: a "hot" bad-prognosis profile, with high lymphocyte infiltration and high expression of immune checkpoints and pro-angiogenic genes; a "cold" bad-prognosis profile, with low lymphocyte infiltration and high expression of pro-angiogenic genes; and a "VEGFR2+/VISTA+" better-prognosis profile, with high expression of immune checkpoint VISTA and pro-angiogenic gene VEGFR2. We validated the gene expression levels at the protein level for a subset of five selected genes belonging to the immune and vascular pathways (CD8A, PDL1, VEGFR3, VEGFR2, and VISTA), in the validation series, and replicated the molecular profiles as well as their prognostic value in the replication series.

INTERPRETATION

The prognosis of MPM is best explained by a continuous model, which extremes show specific expression patterns of genes involved in angiogenesis and immune response.

Pleurectomy/decortication and hyperthermic intrathoracic chemoperfusion using cisplatin and doxorubicin for malignant pleural mesothelioma

Background

Malignant pleural mesothelioma (MPM) is an aggressive malignancy with few long-term survivors. Despite the dismal prognosis, hyperthermic intrathoracic chemoperfusion (HITHOC) was shown to improve survival in a selective group of patients. We analyzed the influence of HITHOC following pleurectomy and decortication on postoperative morbidity and overall survival for patients suffering from localized mesothelioma.

Methods

From 2009 until 2013, 71 patients with localized pleural mesothelioma underwent pleurectomy and decortication followed by HITHOC with cisplatin and doxorubicin. We analyzed postoperative morbidity, age, overall survival and influence of macroscopic resection on survival.

Results

Median patient age was 70 years (range, 65-73 years). Patients having the sarcomatoid subtype of mesothelioma showed a poor median survival of 9.2 months. In contrast, patients having the epithelioid subtype had a median survival of 17.9 months. Patients following macroscopic complete resection had a significantly better survival with 28.2 months compared to 13.1 months in patients with incomplete resection of the mesothelioma (P<0.0001). HITHOC was performed in all patients after tumor resection using cisplatin and doxorubicin.

Conclusions

Taken together, HITHOC following pleurectomy and decortication is supposed to be a safe therapeutic option for selected patients with localized epithelial pleural mesothelioma.

Tomotherapy in malignant mesothelioma: a planning study to establish dose constraints

PURPOSE

A planning study was performed for helical tomotherapy treatment. We evaluated the maximum achievable protection of organs at risk (OARs) in patients with malignant pleural mesothelioma after pleurectomy with simultaneous optimal target coverage.

MATERIALS AND METHODS

The datasets of 13 patients were included. The applied dose to the planning target volume (PTV) was 50.4 Gy with single doses of 1.8 Gy per fraction. Presuming optimal target coverage, we evaluated the applied dose to the OARs with special regard to the contralateral lung.

RESULTS

For left-(lsRT)/right(rsRT)-sided radiotherapy, target coverage for the PTV showed a D98 (mean) of 49.37/49.71 Gy (98.0%/98.6%) and a D2 (mean) of 54.19/54.61 Gy (107.5%/108.3%). The beam-on time was kept below 15 min. The achieved mean dose (D50) to the contralateral lung was kept below 4 Gy for lsRT and rsRT. With regard to the other organs at risk the applied doses were as follows: mean dose (lsRT): ipsilateral kidney (Dmean) 13.03 (5.32-22.18) Gy, contralateral kidney (Dmean) <2.0 Gy, heart (Dmean) 22.23 (13.57-27.72) Gy, spinal cord D1 <Gy; mean dose (rsRT): ipsilateral kidney (Dmean) 10.22 (6.30-18.04) Gy, contralateral kidney (Dmean) <2.1 Gy, heart (Dmean) 8.02 (6.0-10.38) Gy, spinal cord D1 <35.5 Gy.

CONCLUSION

With helical tomotherapy, postoperative treatment for malignant pleural mesothelioma after pleurectomy achieves good target coverage combined with simultaneous dose sparing to the (especially contralateral) OARs.

Localized malignant pleural mesothelioma mimicking an anterior mediastinal tumor

Localized malignant pleural mesothelioma (LMPM) is an extremely rare tumor. We report the case of a 40-year-old Japanese male with an LMPM mimicking an anterior mediastinal tumor due to invasion to the anterior mediastinum, and we discuss mainly the differentiation of LMPM from an anterior mediastinal tumor. The present tumor had a long shape along the pleura, and LMPM could be one of the differential diagnoses.

Hyperthermic Intrathoracic Chemotherapy (HITHOC) for Pleural Malignancies-Experience from Indian Centers

Hyperthermic intrathoracic chemotherapy (HITHOC) has been used in addition to radical surgery for primary and secondary pleural malignancies to improve local control, prolong survival, and improve the quality of life. This study was performed to study the indications, methodology, perioperative outcomes, and survival in patients undergoing HITHOC at Indian centers. A retrospective analysis of prospectively collected demographic and clinical data, perioperative and survival data of patients undergoing surgery with or without HITHOC was performed. From January 2011 to May 2018, seven patients underwent pleurectomy/decortication (P/D) or extrapleural pneumonectomy (EPP) with HITHOC and four had P/D or EPP alone at three Indian centers. P/D was performed in two and EPP in nine patients. The primary tumor was pleural mesothelioma in eight, metastases from thymoma in one, germ cell tumor in one, and solitary fibrous tumor of the pleura in one. HITHOC was performed using cisplatin. Grade 3-4 complications were seen in one patient in the HITHOC group and none in the non-HITHOC group, and one patient in the non-HITHOC group died of complications. At a median follow-up of 9 months, five patients of the HITHOC group were alive, four without recurrence, and one with recurrence. One patient in the non-HITHOC group was alive and disease-free at 24 months, and two died of progression at 18 and 36 months. HITHOC can be performed without increasing the morbidity of P/D or EPP. Most of these patients require multimodality treatment and are best managed by multidisciplinary teams.

Molecular pathways and diagnosis in malignant mesothelioma: A review of the 14th International Conference of the International Mesothelioma Interest Group

The pathologist plays a central role in the diagnosis and management of malignant mesothelioma, including definitive tissue-based diagnosis in conjunction with clinical and radiographic data; diverse ancillary studies of diagnostic, prognostic, and predictive importance; and research efforts to better define the pathobiology of mesothelioma and develop novel clinical applications. The pivotal role of pathology in care of mesothelioma patients was on display at the recent meeting of the International Mesothelioma Interest Group (iMig) in Ottawa, Canada. This review summarizes the key findings of the "Molecular Pathways and Diagnosis in Malignant Mesothelioma" plenary session, including a large multi-institutional validation of a composite nuclear grading system for pleural mesothelioma, including incorporation of tumor necrosis as an additional independent prognostic factor; the correlation between nuclear grading in small biopsies and paired resection specimens in pleural mesothelioma; a multi-institutional study of important clinical and pathologic prognostic factors in peritoneal mesothelioma; the diagnostic role of HEG1 immunohistochemistry as a highly sensitive and specific marker of mesothelial lineage; the prevalence and diagnostic significance of MET protein overexpression in mesothelioma, as well as the correlation between MET protein overexpression and MET gene amplification; and the prognostic role of EZH2 protein overexpression in mesothelioma, together with data indicating an important pathogenic role for EZH2 in mesothelioma tumorigenesis. Special consideration is given to the convergence of diagnostic, prognostic, and predictive tools and their role in guiding highly personalized patient-centered management, and to the translation of novel research findings to practical techniques for routine pathologic practice.

Extended pleurectomy decortication: the current role

Extended pleurectomy/decortication (EPD) has been formally defined but there remain technical areas of debate between practitioners. This is partly attributable to the relative rarity of this operation which is largely confined to a small number of specialist centres. Nevertheless, there is a widespread acceptance that extended pleurectomy/decortication (P/D) is a realistic and favourable alternative to extrapleural pneumonectomy. There may, however, remain a small number of clinical cases where this more extensive operation may be indicated. Preservation of the lung has widened the selection criteria for this form of radical mesothelioma surgery but there remain important factors to consider when offering extended P/D. In many patients with poorer prognostic factors the less radical operation of video assisted partial pleurectomy may be preferable. However, a randomized trial showed no survival benefit for this operation over simple talc pleurodesis. The future for P/D may also lie in the outcome of the MARS2 randomized controlled trial which will report in the next few years. Meanwhile there is a clinical and ethical dilemma when asked to perform this operation outside of the context of a clinical trial in the face of the lack of high grade evidence. The role of P/D is in one respect expanding but this may be short lived pending the findings of its assessment against non-surgical treatment.