Background: There are few reports concerning treatment strategies and their contributions to survival of patients with malignant mesothelioma (MM) in Japan.
Material and methods: We extracted all death cases due to MM between 2003 and 2008. The diagnosis of MM was confirmed in 929 cases. Histological subtypes was determined in 709 cases, including 396 (55.9%) epithelioid, 154 (21.7%) sarcomatoid, 126 (17.8%) biphasic, and 33 (4.7%) other types.
Results and conclusion: Median overall survival (OS) of all MM cases was 7.7 months (95% confidence interval, 7.1-8.3). Median OS of patients with epithelioid MM was significantly longer than that of patients with biphasic (p = 0.030) or sarcomatoid (p < 0.001) MM. Surgical resection was performed in 172 patients (18.5%) and 449 (48.3%) received systemic chemotherapy. Survival of patients treated with both surgery and systemic chemotherapy was favorable. Median OS of patients in the late phase of the study period (2006-2008) was significantly longer than that in the early phase (2003-2005) (8.1 vs. 7.5 months, p = 0.008). Independent favorable prognostic factors included age younger than 70 years, female gender, epithelioid subtype, and clinical stage I-III. Multivariate analysis demonstrated that patients who had radical surgery and systemic chemotherapy showed a longer survival, though this could be due to selection bias of patients.