Malignant mesothelioma in the Veneto Region (North-east of Italy), 1988-2002: incidence, geographical analysis, trends and comparison with mortality

Objective: the study assesses incidence and trend of malignant mesothelioma (MM), and mortality from primary pleural tumour (PPT) among residents of the Veneto region (North-east of Italy, 4,450,000 inhabitants at the last census). The study also aims at identifying areas at high risk, by applying geographical analysis techniques. Method: the results have been obtained through the activity of a Mesothelioma Registry, established in 2001, thus collecting largely retrospective data. Incidence and trends are estimated on MM diagnosed between 1988 and 2002 by means of histological or cytological techniques. Deaths from PPT are derived through the availability of mortality records for the period 1988-1999 (latest year available). Direct age-standardization was applied to provincial rates (7 provinees), whereas standardized mortality and incidence ratios according to Kernel estimates and spatial scan statistics have been used to identify clusters at the municipality level (581 municipalities). Results and conclusions: the incidence of MM in the Veneto region appears similar to that of other northern Italian regions (904 new MM cases from 1988 to 2002, 650 among males,.819 pleural, age-standardized annual incidence rates x 100, 000 in the period 1988-1999): 1.75 (IC 95% 1.59-1.91) among males, based on 460 cases, and 0.67 (IC 95% 0.57-0.77) among females, based on 196 cases, and displays an increasing trend among both genders. Among males incidence doubles during the study period. High risks are detected among males in a cluster formed by the city of Venice and surrounding municipalities (Standardized Incidence Ratio, SIR, for pleural mesothelioma, 1988-1999, 2.94 (p=0.001) for the cluster based on 110 observed cases), and, in addition to Venice, in the province of Padua among females (SIR from pleural mesothelioma, 1988-1999, 1.98 (p=0.001) for the cluster based on 95 observed cases). Mortality from TPP turns out to be higher than incidence and tends to approach incidence in more recent years; this may be explained by the increasing application of diagnostic procedures, inclusive of histopathological tests, among old patients.