The estimated incidence of gastrointestinal stromal tumors in France. Results of PROGIST study conducted among pathologists

The aim of this study was to investigate the incidence of gastrointestinal stromal tumors (GISTs) in France. Method. This prospective epidemiological study was performed among pathologists who were asked to report exhaustively the cases of GIST over a one-year period. Results. Five hundred ninetyone cases of GISTs were reported, 535 new cases and 56 cases of relapse. So, the estimated incidence of GIST in France was 8.5-10 cases per million inhabitants in 2005. The main characteristics of the new GIST cases were as follows: mean age 65 (± 13.2) years; 48.6% men; circumstances of discovery: fortuitous 30.5%, symptomatic 46.5%, and unknown 23%. The primary tumor locations were stomach 63.7%, small intestine 21.5%, mesentery 6.5%, colon and rectum 3.2%, esophagus 0.7%, and 4.3% locations were listed as unknown. Globally, 95.3% of GISTs were cKIT (CD117) positive. Based on tumor size and mitotic rate, among the 490 localized GISTs, 14.7% were considered to have a very low prognostic risk, 25.5% low risk, 23.1% intermediate risk, and 23.1% high risk. Conclusions. This study provides for the first time an estimation of the incidence of GISTs in France, and the results are comparable to what has been reported in studies in other European countries.