Background: Thoracoscopy appears to be essential in identifying tumors at the beginning of pleural disease.
Methods: Between 1973 and 1990, diagnostic thoracoscopy was carried out in a prospective series of 188 patients with malignant pleural mesothelioma (MPM). Biopsy samples were obtained in all cases, and diagnosis was confirmed by the French panel of mesothelioma specialists. In all patients we noted the degree of involvement of the parietal, diaphragmatic, or visceral pleura, and classified patients according to the Butchart system: Stage I (66 patients), II (110 patients), III (4 patients), and IV (8 patients). To assess prognostic factors, a multivariate analysis of clinical and endoscopic findings was performed according to the Cox model.
Results: The most favorable factors were absence of weight loss at the time of diagnosis, absence of involvement of the visceral pleura, Butchart Stage I, and epithelial histopathologic type. When Stage I patients were subdivided into two groups according to whether or not they displayed involvement of the visceral pleura, a significant difference in survival was noted (32.7 months versus 7 months, respectively; P < 0.001).
Conclusions: Based on these findings, we propose to divide Butchart or Mattson Stage I into two subgroups, i.e., Stage IA in which only the parietal or diaphragmatic pleura is involved and Stage IB in which the visceral pleura is invaded. In the International Union Against Cancer (UICC) classification, T1 should be used for tumors restricted to the parietal or diaphragmatic pleura and T2 for tumors with additional involvement of the visceral pleura.