Standardizing surgical treatment in malignant pleural mesothelioma

Malignant pleural mesothelioma: The disdained member of thoracic oncology!

Pleural mesothelioma is a very aggressive malignancy that arises from the pleural mesothelial cell lining and is linked strongly to prior asbestos exposure. The ban on asbestos has helped to lower the incidence, but in developing countries like India, it is expected to rise. It has an extended latency period usually progressing over decades and presents with nonspecific symptoms. It has a median survival ranging between 10-22 months. The diagnosis of malignant pleural mesothelioma is challenging and is done using computed tomography (CT), magnetic resonance imaging, or positron emission tomography-CT, with the last two predicting the resectability of the tumor better than CT alone. A pleural biopsy along with an array of immunohistochemical markers, such as p16, BRCA1 associated protein 1, and claudin-4, are required for a definitive diagnosis. Several genetic alterations have prognostic significance as well. The current histological subtype identification is indispensable for decision making because of the new therapeutic avenues being explored. The combination of nivolumab and ipilimumab-based immunotherapy outperformed platinum and pemetrexed-based chemotherapy in terms of survival benefit and improved quality of life especially for non-epithelioid subtypes. However, the latter continues to be a robust treatment option for patients with the epithelioid subtype. Surgery is recommended for resectable cases with radiotherapy being indicated in neoadjuvant, adjuvant, and palliative settings along with systemic treatment. This review article provides an overview of epidemiology, etiology, clinical manifestations, diagnostic approaches (including immunohistochemical and genetic markers), staging, and multidisciplinary approaches to current treatment for malignant pleural mesothelioma using surgery, chemotherapy, immunotherapy, and radiotherapy. It also sheds light on some recent studies (EMPHACIS, CALGB30901, Checkmate-743, etc.) that have led to significant developments in recent years with clinically meaningful results.

Hyperthermic intrapleural chemotherapy: an update

The safety and efficacy of hyperthermic intrathoracic chemotherapy (HITHOC) as an adjunct to cytoreductive surgery (CRS) in pleural malignancies has been well demonstrated. This is most often described in cases of mesothelioma, thymoma, or other secondary pleural metastases. The utilization of a direct cytotoxic agent with increased penetration secondary to a hyperthermic environment is especially beneficial in pleural malignancy as a microscopic resection remains immensely challenging. Despite favorable outcomes with a limited associated risk profile, there persists a variety in utilization and technique of HITHOC described in current literature. National Comprehensive Cancer Network (NCCN) guidelines state that though intraoperative adjuvant therapies such as HITHOC have been studied, they remain of unclear benefit and definitive recommendations do not currently exist. This ambiguity limits the standardization of HITHOC, thus hindering its further application in a patient population with exceedingly poor outcomes within current guideline-based therapy. As the prevalence of pleural malignancies necessitating CRS with adjuvant HITHOC remains quite low, we believe a task force initiative to further investigate the role of HITHOC in surgical management of pleural malignancies would enable wider utility of this promising technique. Additionally, we propose that the creation of a pleural cancer index could aid in standardization of HITHOC in those with pleural malignancy.

Current Management and Future Perspective in Pleural Mesothelioma

Pleural mesothelioma is an aggressive malignancy arising from pleural mesothelial cell lining, predominantly associated with prior exposure to asbestos. The ban on asbestos use has led to its lower incidence in many countries, but globally the disease burden is expected to rise. Therefore, well-planned research is needed to develop more effective, tolerable and affordable drugs. The development of novel treatment has been too slow, with only two regimens of systemic therapy with robust phase 3 data approved formally to date. The treatment scenario for resectable disease remains controversial. However, recent developments in the understanding of disease and clinical trials have been encouraging, and may add better treatment options in the coming years. In this review, we discuss the current treatment options for pleural mesothelioma and shed light on some recent studies and ongoing trials.

[The Current Therapy of Asbestos-Associated Malignant Pleural Mesothelioma - An Expert Consensus Paper]

Asbestos-related mesotheliomas belong to the group of the most frequent occupational diseases in Germany, reaching about 1,000 new cases per year. The disease has a dismal prognosis because most tumors remain asymptomatic for a long time and therefore are diagnosed as incidental findings at later stages.During the last decade the German Social Accident Insurance (DGUV) has made considerable efforts to prepone the diagnosis in order to detect the disease at earliest possible stages. These efforts resulted in new findings showing that, in a high-risk group, a combination of the biomarkers calretinin and mesothelin was able to advance the diagnosis up to 12 months.Ideally, the diagnosis of a mesothelioma at an early stage has to be accompanied by the best possible individualized therapy. Standard therapeutic strategies are surgery and chemotherapy, added by radiotherapy and psycho-oncology. In recent years, several new therapeutic avenues are being explored. This review comprehensively presents both old and new therapeutic options in mesothelioma, based on international Leitlinien and new studies.

Emerging Treatments for Malignant Pleural Mesothelioma: Where Are We Heading?

Malignant pleural mesothelioma (MPM) is an uncommon but aggressive and treatment resistant neoplasm with low survival rates. In the last years we assisted to an exponential growth in the appreciation of mesothelioma pathobiology, leading several new treatments to be investigated both in the early stage of the disease and in the advanced setting. In particular, expectations are now high that immunotherapy will have a leading role in the next years. However, caution is required as results from phase II studies in MPM were often not replicated in larger, randomized, phase III trials. In this review, we describe the most promising emerging therapies for the treatment of MPM, discussing the biological rationale underlying their development as well as the issues surrounding clinical trial design and proper selection of patients for every treatment.

Current Management of Pleuropulmonary Blastoma: A Surgical Perspective

Pleuropulmonary blastomas (PPB) are pediatric, embryonal cancers of the lung parenchyma and pleural surfaces and are among the most common DICER1-related disorders. These tumors undergo evolution through several forms, allowing division into types I, Ir, II, and III, with correlates to the age of diagnosis and prognosis. We sought to provide a comprehensive review of the relevant literature describing the characteristics of these tumors and their multidisciplinary treatment, with an emphasis on surgical management. We describe the complementary roles of chemotherapy and surgery in the successful management of this disease. We discuss the timing of surgery and options for surgical approaches. We address the differentiation of PPB from congenital pulmonary airway malformation and the role of DICER1 testing for children with pulmonary cysts.

Mutational Profiling of Malignant Mesothelioma Revealed Potential Therapeutic Targets in EGFR and NRAS

Pemetrexed and platinum (PP) combination chemotherapy is the current standard first-line therapy for treatment of malignant mesothelioma (MM). However, a useful predictive biomarker for PP therapy is yet to be found. Here, we performed targeted exome sequencing to profile somatic mutations and copy number variations in 12 MM patients treated with PP therapy. We identified 187 somatic mutations in 12 patients (65 synonymous, 102 missense, 2 nonsense, 5 splice site, and 13 small coding insertions/deletions). We identified somatic mutations in 23 genes including BAP1, TP53, NRAS, and EGFR. Interestingly, rare NRAS p.Q61K and EGFR exon 19 deletions were observed in 2 patients. We also found somatic chromosomal copy number deletions in CDKN2A and CDKN2B genes. Genetic alteration related to response after PP therapy was not found. Somatic mutation profiling in MM patients receiving PP therapy revealed genetic alterations in potential therapeutic targets such as NRAS and EGFR. No alterations in genes with potential predictive role for PP therapy were found.

Pleurectomy and decortication

Pleurectomy and decortication (P/D) improve survival and quality of life in selected patients with malignant pleural mesothelioma. The operative procedure was not standardized until recently. The goal of the operation is to perform a macroscopic complete resection of the tumor. This often involves resection of the parietal and visceral pleura and invariably a partial or complete resection and prosthetic reconstruction of ipsilateral hemidiaphragm. We describe our operative planning and technique as well as outcomes of P/D reported in current literature.

The evolution of the diminishing role of extrapleural pneumonectomy in the surgical management of malignant pleural mesothelioma

Malignant pleural mesothelioma is an uncommon and aggressive thoracic malignancy that is rarely curable, even when multimodality therapy is used. Systemic chemotherapy is the primary treatment for the majority of patients with this disease; however, surgical resection may benefit a subset of patients with early-stage disease. The surgical approach that offers the best outcomes remains an area of controversy, with data from retrospective comparisons being the only guide. Historically, extrapleural pneumonectomy (EPP) has been the standard procedure, carrying with it a cost of significant morbidity and impact on quality of life that has raised questions regarding its routine application. Over the past two decades as surgical techniques have been refined and survival data with EPP in large case series have been reported, the paradigm has evolved toward the use of lung-sparing pleural resections such as pleurectomy/decortication (P/D) and extended P/D. The identification of patients who may benefit from EPP over pleurectomy has proven problematic, and the larger question regarding the impact of any type of surgical intervention on outcomes for pleural mesothelioma patients is still an area of investigation. Uniform treatment approaches have been difficult to develop due to the relatively small numbers of patients with this disease, the use of a staging system that does not readily identify those who may benefit from more aggressive therapy, and the institutional biases that have resulted from the growth of multimodality centers of excellence.

Surgical management of malignant pleural mesothelioma: impact of surgery on survival and quality of life-relation to chemotherapy, radiotherapy, and alternative therapies

Introduction. Malignant pleural mesothelioma (MPM) is an aggressive cancer arising from pleural mesothelium. Surgery aims to either cure the disease or control the symptoms. Two surgical procedures exist: extrapleural pneumonectomy (EPP) and pleurectomy/decortication (P/D). In this systematic review we assess current evidence on safety and efficacy of surgery. Methods. Five electronic databases were reviewed from January 1990 to January 2013. Studies were selected according to a predefined protocol. Primary endpoint was overall survival. Secondary endpoints included quality of life, disease-free survival, disease recurrence, morbidity, and length of hospital stay. Results. Sixteen studies were included. Median survival ranged from 8.1 to 32 months for P/D and from 6.9 to 46.9 months for EPP. Perioperative mortality was 0%–9.8% and 3.2%–12.5%, respectively. Perioperative morbidity was 5.9%–55% for P/D and 10%–82.6% for EPP. Average length of stay was 7 days for P/D and 9 days for EPP. Conclusion. Current evidence cannot definitively answer which procedure (EPP or P/D) is more beneficial in terms of survival and operative risks. This systematic review suggests that surgery in the context of trimodality therapy offers acceptable perioperative outcomes and long-term survival. Centres specialising in MPM management have better results.