Extrapleural pneumonectomies for pleural mesothelioma

Introduction: Malignant pleural mesothelioma (MPM) is a fatal malignancy for which there is no definitive cure. The most effective multimodality treatment in prolonging survival is still matter of debate. Surgery remains one of the cornerstones in the multimodality therapy for MPM. Extra-pleural pneumonectomy and pleurectomy/decortication are the two main curative-intent procedures; however, the superiority of one technique over the other is still debated. This review aims to assess short- and long-term results of extrapleural pneumonectomy for MPM.Areas covered: This article focuses on the role of extrapleural pneumonectomy in MPM. A systematic review was performed by using electronic databases to identify studies that included patients treated by this procedure for MPM. Endpoints included overall survival, disease-free survival, recurrence rate, perioperative mortality, and morbidity.Expert commentary: This paper offers an overview of the results that are currently obtained in patients undergoing extrapleural pneumonectomy for MPM. The benefit of surgical treatments in MPM is still debated and its primary goal should be the achievement of a macroscopic complete resection. Several alternative multimodality protocols exist, with specific advantages and drawbacks; therefore, individualization of care for each patient is fundamental. The complexity of the surgical treatment mandates that patients be referred to specialized centers.

Target therapy: new drugs or new combinations of drugs in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a disease with a poor prognosis due to its aggressive nature. The management of patients with MPM is controversial. Considering that the contribution of surgery and radiation therapy in the management of this disease is not yet established, systemic treatments are predominantly considered during the course of MPM. Unfortunately, the currently therapeutic armamentarium is scarce and its outcomes still appear modest. New treatment strategies are needed. In preclinical setting, cell cycle regulation, apoptosis, growth factor pathways, and angiogenesis pathways involved in the development of MPM have been identified. However, in clinical setting, several drugs targeting these pathways resulted without a significant activity. A deeper knowledge of the biology and pathogenesis of this disease is required to develop more effective tools for diagnosis, therapy and prevention. This paper reviews therapeutic advances in MPM, with a particular focus on new drugs and new association of drugs of target therapy.

Induction chemotherapy vs post-operative adjuvant therapy for malignant pleural mesothelioma

INTRODUCTION

Malignant pleural mesothelioma (MPM) is an aggressive neoplasia. Multidisciplinary treatments, including the association of induction and/or adjuvant therapeutic regimens with surgery, have been reported to give encouraging results. Current therapeutic options are not well standardized yet, especially regarding the best association between surgery and medical treatments. The present review aims to assess safety, efficacy and outcomes of different therapies for MPM. Areas covered: This article focuses on the multimodality treatment of mesothelioma. A systematic review was performed by using electronic databases to identify studies that considered induction and adjuvant approaches in MPM therapy in a multidisciplinary setting, including surgery. Endpoints included overall survival, disease free survival, disease recurrence, and complications. Expert commentary: This systematic review offers a comprehensive view of current multidisciplinary therapeutic strategies for MPM, suggesting that multimodality therapy offers acceptable outcomes with better results reported for trimodality approaches. Individualization of care for each patient is fundamental in choosing the most appropriate treatment. The growing complexity of treatment protocols mandates that MPM patients be referred to specialized Centers, in which every component of the interdisciplinary team can provide the necessary expertise and quality of care.

SORORIN and PLK1 as potential therapeutic targets in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive type of cancer of the thoracic cavity commonly associated with asbestos exposure and a high mortality rate. There is a need for new molecular targets for the development of more effective therapies for MPM. Using quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) and an RNA interference-based screening, we examined the SORORIN gene as potential therapeutic targets for MPM in addition to the PLK1 gene, which is known for kinase of SORORIN. Following in vitro investigation of the effects of target silencing on MPM cells, cell cycle analyses were performed. SORORIN expression was analyzed immunohistochemically using a total of 53 MPM samples on tissue microarray. SORORIN was found to be overexpressed in the majority of clinical MPM samples and human MPM cell lines as determined by qRT-PCR. Gene suppression of each SORORIN and PLK1 led to growth inhibition in MPM cell lines. Knockdown of SORORIN showed an increased number of G2M-phase population and a larger nuclear size, suggesting mitotic arrest. High expression of SORORIN (SORORIN-H) was found in 50.9% of all the MPM cases, and there is a tendency towards poorer prognosis for the SORORIN-H group but the difference is not significant. Suppression of SORORIN with PLK1 inhibitor BI 6727 showed a combinational growth suppressive effect on MPM cell growth. Given high-dose PLK1 inhibitor induced drug-related adverse effects in several clinical trials, our results suggest inhibition SORORIN-PLK1 axis may hold promise for the treatment of MPMs.

Kinesin family members KIF11 and KIF23 as potential therapeutic targets in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a rare and aggressive form of cancer commonly associated with asbestos exposure that stems from the thoracic mesothelium with high mortality rate. Currently, treatment options for MPM are limited, and new molecular targets for treatments are urgently needed. Using quantitative reverse transcription-polymerase chain reaction (RT-PCR) and an RNA interference-based screening, we screened two kinesin family members as potential therapeutic targets for MPM. Following in vitro investigation of the target silencing effects on MPM cells, a total of 53 MPMs were analyzed immunohistochemically with tissue microarray. KIF11 and KIF23 transcripts were found to be overexpressed in the majority of clinical MPM samples as well as human MPM cell lines as determined by quantitative RT-PCR. Gene knockdown in MPM cell lines identified growth inhibition following knockdown of KIF11 and KIF23. High expression of KIF11 (KIF11-H) and KIF23 (KIF23-H) were found in 43.4 and 50.9% of all the MPM cases, respectively. Patients who received curative resection with tumors displaying KIF23-H showed shorter overall survival (P=0.0194). These results provide that inhibition of KIF11 and KIF23 may hold promise for treatment of MPMs, raising the possibility that kinesin-based drug targets may be developed in the future.

Loss of the deubiquitylase BAP1 alters class I histone deacetylase expression and sensitivity of mesothelioma cells to HDAC inhibitors

Histone deacetylases are important targets for cancer therapeutics, but their regulation is poorly understood. Our data show coordinated transcription of HDAC1 and HDAC2 in lung cancer cell lines, but suggest HDAC2 protein expression is cell-context specific. Through an unbiased siRNA screen we found that BRCA1-associated protein 1 (BAP1) regulates their expression, with HDAC2 reduced and HDAC1 increased in BAP1 depleted cells. BAP1 loss-of-function is increasingly reported in cancers including thoracic malignancies, with frequent mutation in malignant pleural mesothelioma. Endogenous HDAC2 directly correlates with BAP1 across a panel of lung cancer cell lines, and is downregulated in mesothelioma cell lines with genetic BAP1 inactivation. We find that BAP1 regulates HDAC2 by increasing transcript abundance, rather than opposing its ubiquitylation. Importantly, although total cellular HDAC activity is unaffected by transient depletion of HDAC2 or of BAP1 due to HDAC1 compensation, this isoenzyme imbalance sensitizes MSTO-211H cells to HDAC inhibitors. However, other established mesothelioma cell lines with low endogenous HDAC2 have adapted to become more resistant to HDAC inhibition. Our work establishes a mechanism by which BAP1 loss alters sensitivity of cancer cells to HDAC inhibitors. Assessment of BAP1 and HDAC expression may ultimately help identify patients likely to respond to HDAC inhibitors.

Blockade of aquaporin 1 inhibits proliferation, motility, and metastatic potential of mesothelioma in vitro but not in an in vivo model

BACKGROUND

Malignant mesothelioma (MM) is an aggressive tumor of the serosal membranes, mostly the pleura. It is related to asbestos exposure and has a poor prognosis. MM has a long latency period, and incidence is predicted to remain stable or increase until 2020. Currently, no biomarkers for a specific targeted therapy are available. Previously, we observed that expression of aquaporin 1 (AQP1) was an indicator of prognosis in two independent cohorts. Here we determine whether AQP1 inhibition has therapeutic potential in the treatment of MM.

METHODS

Functional studies were performed with H226 cells and primary MM cells harvested from pleural effusions. AQP1 expression and mesothelial phenotype was determined by immunohistochemistry. AQP1 function was inhibited by a pharmacological blocker (AqB050) or AQP1-specific siRNA. Cell proliferation, migration, and anchorage-independent cell growth were assessed. A nude mouse heterotopic xenograft model of MM was utilised for the in vivo studies.

RESULTS

Inhibition of AQP1 significantly decreases cell proliferation, metastatic potential, and motility without inducing nonspecific cytotoxicity or increasing apoptosis. In vivo blockade of AQP1 had no biologically significant effect on growth of established tumours.

CONCLUSIONS

Targeted blockade of AQP1 restricts MM growth and migration in vitro. Further work is warranted to fully evaluate treatment potential in vivo.

Vinorelbine in pemetrexed-pretreated patients with malignant pleural mesothelioma

BACKGROUND

Pemetrexed-platinum chemotherapy is the standard first-line treatment of unresectable malignant pleural mesothelioma (MPM). At progression, patients are generally selected to experimental trials, when available, or, in every-day clinical practice, they are offered second-line chemotherapy. The optimal treatment has not yet been defined. The aim of this retrospective, single-center study was to evaluate the activity and toxicity of vinorelbine administered to a consecutive series of pemetrexed-pretreated MPM patients.

METHODS

Vinorelbine 25 mg/m(2) was administered intravenously as a single agent on days 1, 8 every three weeks, either as second-line (2L) or further-line (>2L) therapy. Treatment was repeated for a maximum of 6 cycles, until progression, or unacceptable toxicity.

RESULTS

Fifty-nine patients were included in this analysis. Vinorelbine was given to 34 patients as 2L, and to 25 as > 2L treatment. The median age was 69 years (range 45-80). Forty-two patients (71.2%) had a good EORTC prognostic score. Partial response was observed in 9 (15.2%) cases, stable disease in 20 (33.9%). The overall disease control rate (DCR) was 49.1%. Median progression-free survival (PFS) and overall survival (OS) were 2.3 and 6.2 months, respectively. ECOG performance status (PS) (HR(0 vs. 1-2) 0.50; 95%CI: 0.3-0.8; p = 0.014) and PFS ≥ 6 months following first-line (FL) chemotherapy (HR(FL-PFS>6 ms vs. <6 ms) 0.50; 95%CI: 0.3-0.9; p = 0.031) were significantly associated to OS in multivariate analysis. No difference was observed in terms of DCR, PFS, and OS in relation to age, histology, sex, line of vinorelbine therapy, or response to FL treatment. Hematological toxicity was acceptable, with grade 3/4 neutropenia occurring in 5 (8.4%) patients, and there were no cases of febrile neutropenia. The main non-hematological toxicities were grade 2 fatigue in 17 (28.8%) and constipation in 7 (11.8%) patients.

CONCLUSIONS

Vinorelbine was moderately active in pemetrexed-pretreated MPM patients, with an acceptable toxicity profile, particularly in patients with ECOG-PS0 and FL-PFS ≥ 6 months.

Which type of surgery should become the preferred procedure for malignant pleural mesothelioma: extrapleural pneumonectomy or extended pleurectomy?

PURPOSES

Since radiation and chemotherapy have limitations as therapies for malignant pleural mesothelioma (MPM). The type of surgery [extrapleural pneumonectomy (EPP), extended pleurectomy (E/P), and pleurectomy/decortication (P/D)] remains controversial.

METHODS

This study involves 76 consecutive patients. 58 of the cases were males (76%) with a median age of 53.17±10.93 years. EPP, E/P, and P/D were performed in 31, 20, and 25 cases, respectively.

RESULTS

The median survival time was 20 months in all patients. Overall, five-year survival rate was 14.3%. The survival rate was significantly better in epithelioid mesothelioma (P=0.049). For EPP cases, the median survival rate was 17 months, and the three-to-five year survival rates were 21% and 17%, respectively. For E/P cases, the median survival rate was 27 months and the three-year and four-year survival rates were 34% and 30%, respectively. For P/D cases, the median survival rate was 15 months and the three-to-five year survival rate was 13% and 0%. There were no statistically significant differences between the three surgical techniques (P=0.088). A comparative analysis indicates only a statistically significant difference in the E/P and P/D comparison (P=0.032). Hospital mortality showed a higher trend in EPP group (EPP: 12.9%, E/P: 0% and P/D: 4%, P=0.145). N2 cases, there were no cases of two-year survival. The survival rate in N2 was comparatively much lower, which was statistically significant (P=0.005). In multivariate analysis, only P/D (OR 0.3, 95% CI: 0.1-0.9, P=0.049) and N2 (OR 1.6, 95% CI: 0.9-2.6, P=0.090) were found to be poor prognostic factors.

CONCLUSIONS

E/P could be encouraged to EPP with lower mortality rate and better survival trend in MPM. N2 diseases were negative prognostic factors in MPM.

Phase II trial of neoadjuvant pemetrexed plus cisplatin followed by surgery and radiation in the treatment of pleural mesothelioma

Background

Malignant pleural mesothelioma is an aggressive tumor that has a poor prognosis and is resistant to unimodal approaches. Multimodal treatment has provided encouraging results.

Methods

Phase II, open-label study of the combination of chemotherapy (pemetrexed 500 mg/m²+cisplatin 75 mg/m² IV every 21 days × 3 cycles), followed by surgery (en-bloc extrapleural pneumonectomy, 3–8 weeks after chemotherapy) and hemithoracic radiation (total radiation beam 54 Gy, received 4–8 weeks post-surgery). The primary endpoint was event-free survival, defined as the time from enrollment to time of first observation of disease progression, death due to any cause, or early treatment discontinuation.

Results

Fifty-four treatment-naïve patients with T1-3 N0-2 malignant pleural mesothelioma were enrolled, 52 (96.3%) completed chemotherapy, 45 (83.3%) underwent surgery, 22 (40.7%) completed the whole treatment including 90-day post-radiation follow-up. The median event-free survival was 6.9 months (95%CI: 5.0-10.5), median overall survival was 15.5 months (95%CI 11.0-NA) while median time-to-tumor response was 4.8 months (95%CI: 2.5-8.0). Eighteen (33.3%) and 13 (24.1%) patients were still event-free after 1 and 2 years, respectively. The most common treatment-emergent adverse events were nausea (63.0%), anemia (51.9%) and hypertension (42.6%).

Following two cardiopulmonary radiation-related deaths the protocol was amended (21 [38.9%] patients were already enrolled in the study): the total radiation beam was reduced from 54 Gy to 50.4 Gy and a more accurate selection of patients was recommended.

Conclusions

The combination of pemetrexed plus cisplatin followed by surgery and hemithoracic radiation is feasible and has a manageable toxicity profile in carefully selected patients. It may be worthy of further investigation.

Trial registration

Clinicaltrial.com registrationID #NCT00087698.

Second-line chemotherapy in malignant pleural mesothelioma: results of a retrospective multicenter survey

The pemetrexed-cisplatin chemotherapy is standard of care in first-line (FL) treatment of malignant pleural mesothelioma (MPM). The second-line (SL) chemotherapy is considered, but the optimal treatment has not been defined yet. The aim of this study was to evaluate the clinical outcomes of SL-therapy in a series of MPM-patients included in a retrospective multicenter database. Clinical records of MPM-patients who received SL-treatment from 1996 to 2008 were reviewed. Study endpoints were response, overall-survival (OS), and progression-free-survival (PFS) for SL, stratified for patient characteristics, FL-outcomes, and type of SL. Out of 423 patients, 181 with full clinical data were identified. Patients' characteristics: median-age 64 years (range: 36-85); male gender 115 (63.5%); good EORTC-score 109 (60.2%); epithelial histology 135 (74.6%). After FL, 147 (81.2%) patients achieved disease-control (DC) and 45 had a time-to-progression≥12 months (TTP≥12). After SL, 95 patients (52.6%) achieved DC (21 response; 74 stable-disease); median PFS and OS were 4.3 and 8.7 months, respectively. According to multivariate analysis, DC after SL-therapy was significantly related to pemetrexed-based treatment (OR: 2.46; p=0.017) and FL-TTP≥12 (OR: 3.50; p=0.006). PFS was related to younger age (<65 years) (HR: 0.70; p=0.045), ECOG-PS0 (HR: 0.67; p=0.022), and FL-TTP≥12 (HR: 0.45; p<0.001). OS was significantly related to ECOG-PS0 (HR: 0.43; p<0.001) and to FL-TTP≥12 (HR: 0.54; p=0.005). In pemetrexed pre-treated patients, re-treatment with a pemetrexed/platinum combination significantly reduced the risk-of-death than pemetrexed alone (HR: 0.11; p<0.001). In conclusion, SL-chemotherapy seems to be active in MPM-patients, particularly in younger patients with ECOG-PS0 and prolonged TTP after FL-pemetrexed-based chemotherapy. In selected patients, re-challenge with pemetrexed-based regimens, preferentially associated with platinum-compound, appears to be an option for SL-setting. Considering the important limitations of this study, due to retrospective nature and the possible selection bias, prospective clinical trials are warranted to clarify these issues.

Advances in the biology of malignant pleural mesothelioma

Malignant pleural mesothelioma is a highly aggressive cancer with a very poor prognosis. Although the mechanism of carcinogenesis is not fully understood, approximately 80% of malignant pleural mesothelioma can be attributed to asbestos fiber exposure. This disease is largely unresponsive to conventional chemotherapy or radiotherapy, and most patients die within 10-17 months of their first symptoms. Currently, malignant pleural mesothelioma therapy is guided by clinical stage and patient characteristics rather than by the histological or molecular features of the tumor. Several molecular pathways involved in malignant pleural mesothelioma have been identified; these include cell cycle regulation, apoptosis, growth factor pathways, and angiogenesis. Unfortunately, several agents targeting these processes, including erlotinib, gefitinib, and imatinib, have proven ineffective in clinical trials. A greater understanding of the molecular pathways involved in malignant pleural mesothelioma is needed to develop better diagnostics, therapeutics, and preventative measures. Moreover, understanding the biological basis of mesothelioma progression may facilitate personalized treatment approaches, and early identification of poor prognostic indicators may help reduce the heterogeneity of the clinical response. This paper reviews advances in the molecular biology of malignant pleural mesothelioma in terms of pathogenesis, the major molecular pathways and the associated therapeutic strategies, and the roles of biomarkers.