Analysis of survival of mesothelioma cases in the Italian register (ReNaM)

Abstract 

The Italian National Mesothelioma Register (ReNaM) was set up at ISPESL (the National Institute for Occupational Safety and Prevention) in 1993. Five Italian regions (Piedmont, Liguria, Emilia-Romagna, Tuscany and Puglia, with a total of approximately 17 500 000 inhabitants) agreed to record mesothelioma cases according to guidelines established by ISPESL, to define exposure to asbestos and transmit the data to ISPESL. We describe an analysis of survival of 429 mesothelioma cases—392 pleural, 34 peritoneal and 3 in the pericardium—diagnosed during 1997, with variable follow-up from June 1999 to December 2001. The Kaplan–Meier method was used to estimate survival rates, the log rank non-parametric test and Cox proportional hazard model to assess the role of prognostic factors such as age, gender, morphology, level of diagnostic certainty and modality of exposure. Median survival was 275 days (95% confidence interval (CI) 241–309) for pleural mesotheliomas and 157 days (95% CI: 118–196) for peritoneal mesotheliomas. Survival after diagnosis of malignant pleural mesothelioma showed a statistically significant linear trend for age group at diagnosis, for males and females (P=0.006 and 0.008, respectively). The Cox proportional hazard model gave an adjusted relative risk (RRadj), for the fibrous histotype, of 2.96 (95% CI: 1.28–6.81; P=0.012) compared with cases with unspecified morphology; for epithelioid and biphasic morphologies, the risk was lower than unity. There was no significant difference in survival for cases with confirmed exposure (occupational, household or environmental) or without.

Keywords:  Mesothelioma, National register, Survival analysis, Prognostic factors