Treatment of Malignant Mesothelioma

Abstract

Malignant pleural mesothelioma (MPM) is a rare tumor that predominantly afflicts men over 50 years of age. Nearly 3000 MPMs are reported annually in the United States with the incidence expected to rise into the new millenium. Over the past 40 years, MPM has been unequivocally linked to asbestos exposure worldwide. Recently, however, a new theory on the carcinogenesis of this tumor has been proposed with the isolation of a simian virus (SV 40)-like gene sequence in mesothelioma tumor cells. The clinical presentation of MPM is variable, although most patients typically present with dyspnea, chest pain, or pleural effusion. Obtaining a diagnosis of MPM has been greatly assisted by video-assisted surgery and the use of immunohistochemistry and electron microscopic techniques, which help distinguish MPM from other tumor pathologies such as adenocarcinoma. Computed tomography and magnetic resonance imaging have been also useful for determining tumor burden and resectability. Traditionally, strategies for the treatment of MPM have included supportive care, surgery, radiotherapy, and chemotherapy. Survival with supportive care alone ranges between 4 and 12 months. Single-modality therapy using traditional approaches (surgery, radiotherapy, chemotherapy) alone has failed to improve patient survival significantly. Recently, results using a multimodality approach have been favorable. In particular, cytoreductive surgery (pleuropneumonectomy) followed by sequential chemotherapy and radiotherapy have demonstrated improved survival, especially for patients with epithelial histology, negative resection margins, and no metastases to extrapleural lymph nodes. Innovative therapies such as the use of photodynamic, targeted cytokines and gene therapy are currently being investigated for management of MPM.