Heterogeneity In The Geographic Distribution Of Diffuse Grade Ii And Iii Gliomas In France

2067 Background: Diffuse WHO grade II and III gliomas (DGII/IIIG) are rare tumors (incidence ≤ 2/105person-years). Specific epidemiological studies are very rare. The main objective of this work is to study the geographical distribution of all newly diagnosed and histologically confirmed DGII/IIIG in metropolitan France. Methods: The methodology is based on a multidisciplinary national network already established by the French Brain Tumor DataBase. Personal addresses at the moment of the surgical procedure for all DGII/IIIG cases were collected for the years 2006-2009. For each area, the incidence of DGII/IIIG was analyzed and standardized on age and sex distribution of the French population (pop). Results: The total number of patients with newly diagnosed and histologically confirmed DGII/IIIG was 4790 (1220, 1190, 1228, and 1152 for years 2006-2009). The Table shows the number of tumors by histology, sex and median age at diagnosis. The overall crude rate was 19.4/106. To enable international comparisons, standardized rates were calculated as follows: 19.8/106 (reference pop, Europe), 18.8/106 (reference pop, US 2000), and 16.0/106 (reference pop, world). The geographic distribution by regions in France showed significant differences. For example, the standardized rates (for 106person-years, 95% confidence intervals, reference pop: France) for Auvergne, Champagne-Ardenne, and Basse-Normandie, were 30.9 (26.4-35.5), 28.5 (24.0-33.0), and 13.9 (10.9-17.0), respectively. Conclusions: To our knowledge, this work is the first to study the geographical distribution of DGII/IIIG across one entire country, and it shows significant heterogeneity. These results will enable to look for different environmental and genetic factors in these different regions. [Table: see text]