Impact of an optimized colonoscopic screening program for patients with Lynch syndrome: 6-year results of a specialized French network

Background: Despite colonoscopic screening, colorectal cancer (CRC) remains frequent in patients with Lynch syndrome (LS). The objective of this study was to evaluate the impact of an optimized colorectal screening program within a French dedicated network. Methods: All LS patients followed at our institution were consecutively included in the Predisposition au Cancer Colorectal-Ile de France (PRED-IdF) network. Patients were offered an optimized screening program allowing an adjustment of the interval between colonoscopies, depending on bowel preparation, chromoendoscopy achievement and adenoma detection. Colonoscopies were defined as optimal when all the screening criteria were respected. We compared colonoscopy quality and colonoscopy detection rate before and after PRED-IdF inclusion, including polyp detection rate (PDR), adenoma detection rate (ADR) and cancer detection rate (CDR). Results: Between January 2010 and January 2016, 144 LS patients were consecutively included (male/female = 50/94, mean age = 51 +/- 13 years and mutations: MLH1 = 39%, MSH2 = 44%, MSH6 = 15%, PMS2 = 1%). A total of 564 colonoscopies were analyzed, 353 after inclusion and 211 before. After PRED-IdF inclusion, 98/144 (68%) patients had optimal screening colonoscopies versus 33/132 (25%) before (p < 0.0005). The optimal colonoscopy rate was 304/353 (86%) after inclusion versus 87/211 (41%) before, (p < 0.0001). PRED-IdF inclusion was associated with a reduction of CRC occurrence with a CDR of 1/353 (0.3%) after inclusion versus 6/211 (2.8%) before (p = 0.012). ADR and PDR were 99/353 (28%) versus 60/211 (28.8%) (p > 0.05) and 167/353 (48.1%) versus 90/211 (42.2%) (p > 0.05), respectively after and before inclusion. Conclusions: An optimized colonoscopic surveillance program in LS patients seems to improve colonoscopic screening quality and might possibly decrease colorectal interval cancer occurrence. Long-term cohort studies are needed to confirm these results.