Epidemiological and Prognostic Differences in Malignant Mesothelioma Between Eastern China and SEER Database.

Eastern China malignant mesothelioma (MM) presents distinct features-younger age, female predominance, and moremalignant peritoneal mesothelioma (MPeM)-contrasting with the Western profile of older males with malignant pleural mesothelioma (MPM). Robust survival data for this population are still unavailable. This retrospective study included 253 MM patients from Zhejiang Cancer Hospital (2010-2024; 222 from Zhejiang Province, ZJ cohort) to update regional epidemiology and compare survival with the Surveillance, Epidemiology, and End Results program (SEER). The ZJ cohort exhibited a younger median age at diagnosis (58 vs. 74 years), a higher proportion of females (62% vs. 24%), and a higher prevalence of MPeM (54% vs. 11%) relative to the SEER cohort. Overall survival (OS) was significantly prolonged in the ZJ cohort (median OS: 22 vs. 10 months), with survival benefits consistently observed across sex, age, and MPM subgroups. Multivariate Cox analysis revealed age as the only consistent independent prognostic factor in both ZJ and SEER cohorts. Following propensity score matching to minimize confounding, the ZJ cohort maintained a significantly longer survival in MPM but exhibited worse outcome in MPeM relative to SEER. Collectively, this study not only updated epidemiologic features for MM in Eastern China but also reported the unique survival patterns, uncovering inter-population heterogeneity. These findings emphasize the value of region-specific prognostic evidence and the limitations of directly applying Western data to Asian populations.