Malignant pleural mesothelioma: overview of the North American and European experience

Stranger Things: New Roles and Opportunities for Androgen Receptor in Oncology Beyond Prostate Cancer

The androgen receptor (AR) is one of the oldest therapeutic targets in oncology and continues to dominate the treatment landscape for advanced prostate cancer, where nearly all treatment regimens include some form of AR modulation. In this regard, AR remains the central driver of prostate cancer cell biology. Emerging preclinical and clinical data implicate key roles for AR in additional cancer types, thereby expanding the importance of this drug target beyond prostate cancer. In this mini-review, new roles for AR in other cancer types are discussed as well as their potential for treatment with AR-targeted agents. Our understanding of these additional functions for AR in oncology expand this receptor's potential as a therapeutic target and will help guide the development of new treatment approaches.

Systematic review of quality of life following pleurectomy decortication and extrapleural pneumonectomy for malignant pleural mesothelioma

BACKGROUND

Few studies have focused on quality of life (QoL) after treatment of malignant pleural mesothelioma (MPM). There are still questions as to which surgical procedure, extrapleural pneumonectomy (EPP) or pleurectomy decortication (P/D) is most effective and results in better survival outcomes, involves fewer complications, and results in better QoL. Here we performed a literature review on MPM patients to assess and compare QoL changes after P/D and EPP.

METHODS

Research articles concerning QoL after mesothelioma surgery were identified through May 2018 in Medline. For inclusion, studies were 1) cohort or randomized controlled trials (RCT) design, 2) included standardized QoL instruments, 3) reported QoL measurement after surgery, 4) described the type of surgery performed (EPP or P/D), 5) were written in English. Measures of lung function (FEV1, FVC) and measures from the EORTC-C30 were compared 6 months following surgery with preoperative values.

RESULTS

QoL data was extracted from 17 articles (14 datasets), encompassing 659 patients (102 EPP, 432 P/D); the available evidence was of low quality. While two studies directly compared QoL between the two surgical procedures, additional data was available from one arm of two RCTs, as the RCTs were not comparing EPP and P/D. The remaining data was reported from observational studies. While QoL was still compromised 6 months following surgery, from the limited and low quality data available it would appear that P/D patients had better QoL than EPP patients across all measures. Physical function, social function and global health were better at follow-up for P/D than for EPP, while other indicators such as pain and cough were similar. Forced Expiratory Volume (FEV1) and Forced Vital Capacity (FVC) were reported in one study only, and were higher at follow-up for P/D compared to EPP.

CONCLUSIONS

Although the existing evidence is limited and of low quality, it suggests that P/D patients have better QoL than EPP patients following surgery. QoL outcomes should be factored into the choice of surgical procedure for MPM patients, and the possible effects on lung function and QoL should be discussed with patients when presenting surgical treatment options.

Ambient Asbestos Fiber Concentrations and Long-Term Trends in Pleural Mesothelioma Incidence between Urban and Rural Areas in the United States (1973-2012)

Over the past 40 years, measured ambient asbestos concentrations in the United States have been higher in urban versus rural areas. The purpose of this study was to determine whether variations in ambient asbestos concentrations have influenced pleural mesothelioma risk in females (who generally lacked historic occupational asbestos exposure relative to males). Male pleural mesothelioma incidence trends were analyzed to provide perspective for female trends. Annual age-adjusted incidence rates from 1973 to 2012 were obtained from the SEER 9, 13, and 18 databases for urban and rural locations, and standardized rate ratios were calculated. Female rural rates exceeded urban rates in almost half of the years analyzed, although the increases were not statistically significant, which is in line with expectations if there was no observable increased risk for urban locations. In contrast, male urban rates were elevated over rural rates for nearly all years examined and were statistically significantly elevated for 22 of the 40 years. Trend analyses demonstrated that trends for females remained relatively constant over time, whereas male urban and rural incidence increased into the 1980s and 1990s, followed by a decrease/leveling off. Annual female urban and rural incidence rates remained approximately five- to six-fold lower than male urban and rural incidence rates on average, consistent with the comparatively increased historical occupational asbestos exposure for males. The results suggest that differences in ambient asbestos concentrations, which have been reported to be 10-fold or greater across regions in the United States, have not influenced the risk of pleural mesothelioma.

Malignant mesothelioma as a difficult interdisciplinary problem

The authors of the present report review the etiology and clinical symptoms of malignant pleural mesothelioma (MPM) as well as diagnostic techniques (both radiological and biomarkers) used for its detection. Subsequently, they present methods of multimodal treatment (surgery, chemotherapy, and radiotherapy) recommended by the International Mesothelioma Interest Group (IMIG). Finally, they discuss complications and long-term results associated with these methods of MPM treatment.

Association Between Clinicopathological Factors and Genomic Abnormalities Detected by FISH Analysis in Epithelioid Diffuse Malignant Pleural Mesothelioma

BACKGROUND

Abnormality of genes including 9p21 is known in malignant mesothelioma and we have examined the frequency of gene deletion and amplification using the fluorescence in situ hybridization (FISH) method. We formerly reported that abnormality of the genes was more common in the sarcomatoid type than epithelioid type. In this study, we compared the clinicopathological factors including nuclear grade (NG) and genomic abnormality in epithelioid malignant pleural mesothelioma (MPM).

METHODS

Using paraffin-embedded tissues of 31 epithelioid MPMs, we investigated the presence of gene abnormalities in the genes 9p21, 1p36, 14q32, 22q12, 5p15, 6p, 8q24, and 7p12 by the FISH method, and compared the results with NG, clinical stage, and prognosis.

RESULTS

In the higher NG group of epithelioid MPM, more gene amplifications [in particular 5p15 and 8q24(MYC)] were observed, and clinical stage was more advanced. Cases with the amplification of 7p12(EGFR) tended to exhibit a worse prognosis. The significant correlation between histological differentiation and clinical features such as prognosis was not confirmed.

CONCLUSIONS

NG status in epithelioid MPM may be related to gene alteration and clinical features.

Characteristics of malignant pleural mesothelioma in women

BACKGROUND

The incidence of malignant pleural mesothelioma (MPM) is higher in men than in women, likely due to increased occupational asbestos exposure among men. Women also appear to experience better long-term survival. This study evaluates the role of gender in relation to established prognostic factors in MPM.

METHODS

We reviewed 715 cases of MPM treated with extrapleural pneumonectomy at our institution between July 1987 and December 2008. Data for patients with epithelial and nonepithelial tumors were analyzed separately. Kaplan-Meier and Cox regression analyses were used to estimate survival for various cohorts to assess the relationship between gender and survival independent of age at surgery, stage, side, and preoperative laboratory studies.

RESULTS

Of the 702 patients with complete data available, 114 out of 450 patients with epithelial tumors and 31 out of 252 patients with nonepithelial histology were women. Women with epithelial (and not nonepithelial) disease were found to differ significantly from men with respect to younger age, higher rate of thrombocytosis, and longer survival after surgery. The effect of gender on survival of patients with epithelial disease persisted when controlling for age, stage, thrombocytosis, leukocytosis, and anemia with a multivariable analysis. No significant differences in survival were seen among patients with nonepithelial disease with regard to gender, age, or anemia.

CONCLUSIONS

In the absence of other negative prognostic factors, women with epithelial MPM demonstrated a survival advantage. These findings support an aggressive approach to treating MPM including extrapleural pneumonectomy in individuals with favorable prognostic predictors, particularly women with epithelial histology and no other risk factors.

What's the place of immunotherapy in malignant mesothelioma treatments?

Malignant pleural mesothelioma (MPM) is a rare malignancy of the pleura with a very poor prognosis. Treatments evaluated for malignant mesothelioma, including chemotherapy, radiotherapy and surgery are of limited efficacy. However, the fact that the tumors of some patients with MPM regress spontaneously or respond to immunotherapy suggests that the immune system may respond to MPM under some circumstances. In this respect, animal studies have demonstrated immunoreactivity of MPM to different immunotherapies. In the case of MPM, several clinical studies have demonstrated a correlation between the presence of a lymphocyte infiltrate and a better prognosis and humoral response directed against specific antigens related to tumor. Thus, MPM immunotherapy is undoubtedly a highly promising but also very challenging approach to the treatment of this disease that has slipped through the defense lines of the immune system. This article reviews past and recent developments of the clinical strategies that concern immunotherapy of mesothelioma.

Asbestos exposure predicts cell cycle control gene promoter methylation in pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a rapidly fatal tumor with increasing incidence worldwide responsible for many thousands of deaths annually. Although there is a clear link between exposure to asbestos and mesothelioma, and asbestos is known to be both clastogenic and cytotoxic to mesothelial cells, the mechanisms of causation of MPM remain largely unknown. However, there is a rapidly emerging literature that describes inactivation of a diverse array of tumor suppressor genes (TSGs) via promoter DNA CpG methylation in MPM, although the etiology of these alterations remains unclear. We studied the relationships among promoter methylation silencing, asbestos exposure, patient demographics and tumor histology using a directed approach; examining six cell cycle control pathway TSGs in an incident case series of 70 MPMs. Promoter hypermethylation of APC, CCND2, CDKN2A, CDKN2B, HPPBP1 and RASSF1 were assessed. We observed significantly higher lung asbestos body burden if any of these cell cycle genes were methylated (P < 0.02), and there was a significant trend of increasing asbestos body counts as the number of methylated cell cycle pathway genes increased from 0 to 1 to >1 (P < 0.005). This trend of increasing asbestos body count and increasing number of methylated cell cycle pathway genes remained significant (P < 0.05) after controlling for age, gender and tumor histology. These data suggest a novel tumorigenic mechanism of action of asbestos and may contribute to the understanding of precisely how asbestos exposure influences the etiology and clinical course of malignant mesothelioma.

Current therapies for malignant pleural mesothelioma

Mesothelioma is a highly lethal tumor derived from mesothelial cells, and its global incidence is increasing because of widespread exposure of numerous individuals to asbestos in the last 50 years. Mesothelioma is largely untreatable with any of the therapeutic modalities. Recently, a novel multitargeted antifolate pemetrexed has shown promising activity against malignant pleural mesothelioma, producing response rates of up to 40% when used in combination with cisplatin. In a large phase III study, use of a combination of pemetrexed and cisplatin was associated with significantly improved survival time and with greater antitumor activity compared with cisplatin alone. This combination also gave a significant response rate of approximately 50% in patients with epithelioid malignant pleural mesothelioma. These clinical benefits of pemetrexed-cisplatin doublet have changed the perception of mesothelioma chemotherapy. Other combinations, including gemcitabine in combination with cisplatin, have also shown encouraging response rates. Prognosis depends on gender, clinical stage of the tumor, histological subtype, platelet count, leukocyte counts, and performance status. Radiotherapy can palliate mesothelioma patients with chest pain, and has been indicated to be of benefit for the prevention of malignant seeding along the tract of a chest tube or needle biopsy. Trimodality treatment using extrapleural pneumonectomy, radiation and chemotherapy has shown promising therapeutic value. The development of chemotherapeutic regimens and the favorable outcomes of trimodality have led to new combined modality trials. In Japan, multicenter national trials against mesothelioma will begin in the near future.

Incidence and descriptive epidemiology of mesothelioma in the United States, 1999-2002

To estimate the recent incidence of mesothelioma in the United States and characterize its descriptive epidemiology, incidence data were obtained from the National Program of Cancer Registries (NPCR) and the Surveillance, Epidemiology and End Results (SEER) Program. Age-adjusted incidence rates and 95% confidence intervals were calculated. The U.S. incidence was 1.11 cases per 100,000 persons. Most cases occurred among older, white males. However, 173 cases (< 2%) occurred in persons younger than 40. The proportion of women with peritoneal mesothelioma was triple that of men (14.8% vs 5.4%). Of 40 reporting states, 11 had incidence rates significantly higher than the national rate.

Radiation-induced cellular DNA damage repair response enhances viral gene therapy efficacy in the treatment of malignant pleural mesothelioma

BACKGROUND

Malignant pleural mesothelioma (MPM) treated with radiotherapy (RT) has incomplete responses as a result of radiation-induced tumoral stress response that repairs DNA damage. Such stress response is beneficial for oncolytic viral therapy. We hypothesized that a combination of RT and NV1066, an oncolytic herpes virus, might exert an additive or synergistic effect in the treatment of MPM.

METHODS

JMN, a MPM cell line, was infected with NV1066 at multiplicities of infection of .05 to .25 in vitro with and without radiation (1 to 5 Gy). Virus replication was determined by plaque assay, cell kill by lactate dehydrogenase assay, and GADD34 (growth arrest and DNA damage repair 34, a DNA damage-repair protein) by real-time reverse transcriptase-polymerase chain reaction and Western blot test. Synergistic cytotoxicity dependence on GADD34 upregulation was confirmed by GADD34 small inhibitory RNA (siRNA).

RESULTS

Synergism was demonstrated between RT and NV1066 across a wide range of doses. As a result of such synergism, a dose-reduction for each agent (up to 5500-fold) can be accomplished over a wide range of therapeutic-effect levels without sacrificing tumor cell kill. This effect is correlated with increased GADD34 expression and inhibited by transfection of siRNA directed against GADD34.

CONCLUSIONS

RT can be combined with oncolytic herpes simplex virus therapy in the treatment of malignant pleural mesothelioma to achieve synergistic efficacy while minimizing dosage and toxicity.

Cardiac tamponade complicating trimodal therapy for malignant mesothelioma

Trimodal therapy, which includes extrapleural pneumonectomy as the cytoreductive procedure followed by combination chemoradiotherapy, is becoming the standard of care in the treatment of malignant mesothelioma. We report here a case of hypotension secondary to tension hydrothorax in which echocardiography and hemodynamic monitoring demonstrated evidence of tamponade physiology. Thoracentesis was lifesaving.

New therapeutic options for mesothelioma

Malignant pleural mesothelioma is an aggressive thoracic tumor that is often refractory to chemotherapy and radiotherapy, making long-term survival a difficult goal. Although multimodality therapies, including cytoreductive surgery, chemotherapy, and radiotherapy, have been tested, their survival benefit is unclear. Recently, novel cytotoxic agents such as pemetrexed have shown promise in the treatment of malignant pleural mesothelioma, and in early trials new small-molecule agents targeted to the specific biochemical properties of this tumor have shown promise.