Review of staging and diagnosis of malignant pleural mesothelioma

Despite the aggressive nature of malignant pleural mesothelioma (MPM) its diagnosis and accurate staging remains elusive. MPM is highly associated with asbestos exposure, but the long latency period makes exposure tracking a challenge. The disease often presents surreptitiously leading to late diagnosis and therefore poor prognosis. Patients often present with symptoms such as dyspnea, chest pain, fatigue, and cough that are suggestive of many thoracic ailments such as lung cancer, pneumothorax, and pneumonia. Consequently, these patients often receive a computerized tomography (CT) scan as the first step towards diagnosis. If the results of the CT scan are suggestive of mesothelioma, such as if diffuse pleural thickening or a rind is seen, a biopsy is the next intervention sought. A thoracoscopic biopsy is often preferred over a core needle biopsy and is paramount for diagnosis and subsequent treatment plan optimization. Positron emission tomography (PET) scans have been useful in determining the spread of the disease while magnetic resonance imaging (MRI) has been a tool in determining respectability. In an effort to optimize care for these patients, staging guidelines have evolved and now align with those utilized with solid tumors such as sarcoma. The current classification system is the eighth edition of the tumor, node, and metastasis (TNM) system published by the International Mesothelioma Interest Group (IMIG) for MPM. This edition incorporates changes in the T and N classifications and differs from previous guidelines that focused on surgical management of the disease. In an effort to improve clinical decision making and prognostication novel staging approaches, including volumetric staging, have been proposed. Diagnosis and treatment of MPM is further complicated by the difference in behavior and tumor marker expression of the epithelioid subtype and the sarcomatoid subtypes. Utilizing computerized databases, literature pertaining to the diagnosis and staging of MPM was analyzed. We focused on the utility of current imaging strategies, staging systems, and pathologic analysis. MPM remains a challenge to diagnose and treat. The increased integration of advanced imaging modalities will likely aid in diagnosis of MPM. Advancements in diagnosis will predictably go hand-in-hand with more precise staging systems that will overall improve prognostication and survival.