Diffuse malignant pleural mesothelioma: A multi-institutional clinicopathological study.

Abstract Purpose  The relative rarity of malignant pleural mesothelioma (MPM) in Japan makes it difficult to perform a large-scale clinicopathological study of this tumor at a single institute. Thus, we performed a multiinstitutional study to evaluate the current status of diagnosis and treatment in Japan. Methods  We analyzed the records of 65 patients with MPM, obtained from the 13 institutions comprising the Japanese Chiba Multicenter Study Group. Results  In 56 patients, the tumor was detected after a visit to a medical facility for subjective symptoms such as chest pain, shortness of breath, and cough. It took a median period of 2 months from the initial visit to establish the diagnosis. The overall survival rates of 33 patients with unresectable MPM 1, 2, and 3 years after the diagnosis were 40.5%, 10.8%, and 0%, respectively, whereas those of 32 patients who underwent surgery were 67.9%, 35.0% and 10.9%, respectively (P = 0.0035). According to multivariate analysis, histological type, International Mesothelioma Interest Group clinical stage, sex, and the presenting symptom of shortness of breath were significant prognostic factors. Conclusions  The definitive diagnosis of early MPM is difficult, but establishing the best diagnostic modality would improve survival rates, since radical surgery is likely to be effective for resectable disease. [ABSTRACT FROM AUTHOR]