Multimodality Therapy for Malignant Pleural MesotheliomaMalignant pleural mesothelioma, a rare disease whose etiology is tied to asbestos exposure, has been steadily increasing in incidence despite industrial regulation of asbestos during the 1960s. As many as 3,000 new cases are expected to be diagnosed in the United States in 1997. The rising incidence can be attributed to the disease’s long exposure-to-diagnosis interval. Left untreated, patients survive a median of 4 to 12 months.
The failure of single-modality and bimodality therapy to improve the survival of patients with malignant pleural mesothelioma led us to evaluate a trimodality approach of extrapleural pneumonectomy followed by combination che-moradiotherapy. Our rationale behind using extrapleural pneumonectomy as opposed to pleurectomy was that a complete or near-complete resection would be expected to improve survival in patients with this primarily locally recurring disease, and that high-dose radiotherapy could be administered without concern for radiation pneumonitis.
Three pathologic subtypes of malignant mesothelioma are recognized: epithelial, sarcomatoid, and mixed histology. Among these, pure epithelial tumors are associated with the best prognosis. The mesothelioma tumor is a relentless, local-growth neoplasia, potentially resulting in myocardial (10%), bowel (33%; secondary to transdia-phragmatic invasion into the peritoneum), mediastinal, or pulmonary involvement.

Malignant pleural mesothelioma is primarily a disease of 50- to 70-year-old men. Approximately 80% of patients present with dyspnea or pleural effusion. Other common presenting symptoms include cough (60%), chest pain (40%), fever, and weight loss. Five percent of patients present with bilateral involvement. In advanced disease, wasting, ascites, or chest wall deformity is seen.
Malignant pleural mesothelioma is not easy to diagnose. For example, only 75 to 80% of patients will have known asbestos exposure. Pleural effusions, with or without pleural calcifications, are commonly noted on chest radiograph. CT (or, more recently, MRI) is a more useful tool for assessing disease spread, particularly beyond the thoracic cavity, whereas echocardiography is helpful in assessing pericardial involvement and ventricular function. The preoperative physiologic status of these patients is evaluated using pulmonary function testing as a screening tool followed by ventilation-perfusion scan in patients who will benefit from extrapleural pneumonectomy. Thoracentesis is sometimes useful in diagnosing mesothelioma, as the pleural fluid obtained is usually yellow in comparison to the sanguineous fluid characteristic of adenocarcinoma. Cytologic examination of the fluid specimen may be helpful, but more commonly, a pleural biopsy specimen is needed for sufficient tissue diagnosis.