Cancers around the Roussillon chemical platform

Abstract

Background The Roussillon region located in the department of Isere, 50 kilometers south of Lyon, is one of the three “multi-exposed” areas identified in the Auvergne-Rhone-Alpes (ARA) region. It concentrates one of the main chemical sites of France, as well as dense road traffic and an important population. The site is subject to global environmental monitoring. Local residents and associations expressed their fear of an excess of environmental-related cancers, which local media relayed. The Regional Health Agency and the Sub-Prefecture of Isere contacted “Sante publique France” to carry out a study to address this fear. Method An ecological study was conducted, analyzing cancer incidence and cancer mortality data over the period 2003–2013 in the six communes bordering the platform (28,000 inhabitants) likely to be the most affected by its activities. The Isere cancer registry is one of the 13 general cancer registries in metropolitan France. It provided the numbers of incident cancer cases by cancer site for each commune of the department. The Center of Epidemiology on Medical Causes of Death (CepiDC) provided data from death certificates, as well as the number of deaths by cancer site, for each commune in the department of Isere. The method of analysis is based on the calculation of the standardized mortality ratio (SMR) and the standardized incidence ratio (SIR). SMRs (SIRs) are the ratios between the number of deaths (cases) observed in the population studied and the number of deaths (of cases) expected in this population if it knew the mortality conditions (of incidence) at each age of the reference population (here the population of the Isere department). The standardized ratios are accompanied by 95% confidence intervals calculated according to the Byar approximation and are then adjusted to take into account a possible over-dispersion of the data greater than the variance of the theoretical model (Poisson's law). The analysis focuses principally on cancer sites for which the pollutants identified in the area are a known or suspected risk factor in the scientific literature. Results The study on all cancers shows a slightly higher incidence of cancers among men living in the area (+8%) and a mortality rate that is not statistically different from the departmental average. For women, incidence of cancer and cancer mortality are at the same level in the area as in the Isere department. Analyzes by cancer localization show that cancers affecting the respiratory tract and mainly the mesothelioma of the pleura are in excess in the Roussillon area. For mesothelioma of the pleura, the risk, in terms of incidence and mortality, is multiplied by more than 5 in the male population of the study (significant results), and by more than 2.5 in women (non-significant results). To a lesser extent, there is an excess mortality from cancers of the larynx, trachea, bronchi and lung in men and women in the sector. No other cancer sites are found in excess among the residents of the chemical platform of Roussillon. Conclusion This study shows an important excess mesothelioma in men living in the communes surrounding the Roussillon chemical platform, largely due to an occupational exposure rather than an environmental exposure, as occupational exposure to asbestos is the main risk factor for mesothelioma. Exposure of asbestos could also explain some of the excess deaths from lung cancer. Asbestos has been used in the Roussillon chemical platform as thermal insulator. An administrative procedure is currently underway to characterize companies of the platform as an “asbestos site”.