Autopsy reports and asbestos exposure from mesothelioma patients: a population-based study in Northeastern Italy.

Abstract

PURPOSE: Malignant Mesotelioma (MM) is known for its association with asbestos exposure and long latency. Few studies examine a large series of MM patients investigating the past exposure intensity by autopsy findings. The aim was to describe the characteristics of MM cases diagnosed in Friuli Venezia Giulia, a region with several shipyards, and to assess past exposure levels by biological/histological markers, paying attention to some parameters of occupational exposure. METHODS: For the period 1995–2023, all MM cases were retrieved from the Regional registry and information on diagnosis and exposure were evaluated. Pleural plaques (PP), lung fibrosis and asbestos bodies (ABs) counts were identified by autopsy reports and their relationship to past asbestos exposure was analyzed. RESULTS: Out of 1756 patients (1,487 men, 269 women; mean age at diagnosis 72.3 ± 10.4 years), autopsy reports were available for 896 cases (763 males and 133 females). PP, lung fibrosis and high ABs count (≥ 10,000 per gram of dry lung tissue) were more often present in men and in occupational exposure group than in women and in non-occupational one (p = 0.01). Among males occupationally exposed to asbestos (567 pleural and 33 peritoneal mesotheliomas), individuals with PP (66% of cases) had a significantly longer duration of exposure (mean 23.4 ± 11.9 versus 21.1 ± 11.7 years, p < 0.05) and latency period (mean 52.0 ± 10.9 versus 50.0 ± 11.4 years, p < 0.05) than those without them (34% of cases). Multivariable analysis confirmed the association between PP and duration of exposure (OR = 1.01; 95% CI 1.00–1.03), presumably due to a greater cumulative exposure in these subjects. CONCLUSION: This study suggests that although autopsy findings in MM patients can support the etiology and the relevance of past asbestos exposure, their absence does not rule out this possibility, especially in medicolegal and insurance contexts. The large series of autopsies confirmed the diagnosis of MM among these patients, improving the level of diagnostic certainty in those for whom asbestos exposure is hardly assessable, such as domestic or environmental exposure.