Résumé
Abstract only 1528 Background: Patients referral to dedicated consultations for cancer predisposition syndrome has become a standard in clinical practice. Based on nationwide data from the French national cancer institute (NCI), we analyzed the evolution of cancer genetics consultations and testing over time, and the uptake of targeted tests in relatives of families with a BRCA1/2 or MMR mutation. Methods: All French cancer genetics centres completed annually a survey collecting standardized parameters for the NCI from 2003 to 2011. We report on the analysis of a total of 240,134 consultations and 134,652 genetic tests that enabled to identify 32,494 mutation carriers. Results: From 2003 to 2011, 141,639 (59 %) and 55,698 (23.2 %) patients were referred for a breast or a colorectal cancer predisposition syndrome, respectively. During this period, we found a dramatic and steadily increase in genetic tests performed for the BRCA1/2 genes (from 2095 to 7393 tests/year, P<0.0001) but not for the MMR genes (from 1144 to 1635/year, P=NS). The percentage of deleterious mutations identified in the probands tested was 13.8 % and 20.9 % in BRCA1/2 and Lynch syndromes, respectively. In families with a BRCA1/2 or a MMR identified mutation, there was an average number of 3.03 relatives performing target tested. Conclusions: This nationwide study shows a lack of referral and genetic testing in Lynch syndrome as compared to BRCA1/2 syndrome. Only a third of relatives for a proband identified with a BRCA1/2 or MMR gene mutations performed a genetic targeted test. Enhanced information about validated benefit of genetic testing should be given to clinicians and patients particularly for Lynch syndrome and for relatives of a proband carrying an identified BRCA1/2 or MMR genes mutation.