Accuracy of mesothelioma occurrence forecasts, characteristics of cases, and incidence rates in Lombardy Region (Northern Italy).

BACKGROUND: in 2016, based on data 2000-2012, using gender-specific age-cohort models, the number of mesothelioma cases in Lombardy were predicted for the period 2013-2029. OBJECTIVES: to evaluate accuracy forecasts for the years 2013-2024; to examine the characteristics of affected subjects and to calculate incidence rates for the years 2000-2021. DESIGN: incidence study. SETTING AND PARTICIPANTS: Lombardy Region (Northern Italy); individuals recorded in the Lombardy Mesothelioma Registry. MAIN OUTCOME MEASURES: mesothelioma incidence. METHODS: the number of observed and predicted cases was compared for the years 2013-2024. Moreover, cases observed in 2000-2021 (years in which all registry activities have been completed) were selected from the registry database, their clinical characteristics and asbestos exposure were described, and crude and age-standardized rates (ASR) were calculated by year and Province of residence. RESULTS: in the years 2013-2024, 3,588 cases were observed in men, 435 more than the predicted value; in women, 1,671 cases were recorded, 90 less than the predicted value. The yearly number of cases was constant in men and slightly declining in women. In the period 2000-2021, 8,437 cases (7,922 pleural mesotheliomas) were recorded and evaluated, 5,568 in men and 2,869 in women. Evidence of occupational exposure was found for about two thirds of men and for one third of women. Most men had been exposed to asbestos in metalworking and metallurgy industries (35.4%) and in the construction sector (33.7%). Most women had been exposed in non-asbestos textile (53.3%) or clothing (13.4%) industries. In both genders, rates decreased for ages below 70 years, were stable for ages 70-74 years, and increased for ages 75+ years. In both genders, the highest rates were recorded in Pavia Province, where an asbestos cement factory had been operating for a long time. CONCLUSIONS: a fair agreement between observed mesothelioma cases and forecasts as of 2024 was found. The peak occurred in 2013, but in the following years there was no indication of decrease of yearly cases in men and only a slight decrease in women. The highest disease burden concerns individuals aged 75 years or more. Data from this paper indicates that in 2025-2029 in Lombardy there still will be between 350 and 400 cases per year.