Peculiar features of mesothelioma as related to exposure patterns and circumstances in the Lombardy Region, Italy

Background: The "Lombardy Mesothelioma Registry" started its activity in 2000 in accordance with Italian law DL 277/91. Objectives and methods: The Registry collects all new incident cases of Malignant Mesothelioma (MM) of pleura, peritoneum, pericardium and vaginal tunic of testis occurring in residents in the Lombardy Region (Northern Italy). For each "possible case" reported to the Registry by Lombardy hospitals, diagnosis is ascertained according to ISPESL Guidelines. For confirmed cases, a standardized questionnaire is administered to the subject or next-of-kin, to verify sources of lifetime asbestos exposure. Descriptive results are given for cases collected in 2000-2001. Age standardized incidence rates for the year 2000 were calculated for males and females. Results: After revision of clinical records, diagnosis was judged as "certain" MM in 307 (60%) subjects, probable in 63 (12%) and possible in 33 (6%) subjects. 21 were peritoneal mesothelioma. Standardized rates for pleural mesothelioma were respectively 3.7 and 1.4 per 100,000 for males and females. Occupational asbestos exposure was ascertained for 71% of male cases and 26% of females. Exposure was unknown in 11% and 27% of males and females respectively. The main relevant exposures were in building trades, metal manufacturing, machine production and maintenance; an unexpectedly high proportion of female cases was engaged in non-asbestos textile factories. Conclusions: The high proportion of cases with unknown exposure underlines the need to explore new tools and sources to ascertain asbestos exposure. An ad hoc survey in textile industries showed exposure to asbestos to be widely spread in this industry.