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 Prédisposition 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.

INTRODUCTION: Colonoscopic screening with indigo carmine chromoendoscopy (ICC) in patients with Lynch syndrome (LS) improves the adenoma detection rate but is time consuming and poorly used in clinical practice. Narrow-band imaging (NBI), a virtual chromoendoscopy technique, highlights superficial mucosal vessels and improves adenoma characterization. We conducted a prospective multicenter trial in a back-to-back fashion to compare the third-generation NBI with ICC for detecting colonic adenomas in patients with LS. METHODS: In a multicenter, prospective, noninferiority trial, 138 patients underwent a double colonoscopy, first with NBI, followed by ICC, in a back-to-back design. The primary noninferiority outcome measure was the number of patients with at least one adenoma after NBI compared with the number of patients with at least one adenoma after NBI and ICC. RESULTS: The 138 analyzable patients were all proven mismatch repair mutation carriers for LS (MLH1 = 33%, MSH2 = 47%, MSH6 = 15%, PMS2 = 4%, and EPCAM = 1%). The mean age (SD) was 40.5 (14.7) years, and 64 (46.4%) were men. The median withdrawal time for an NBI procedure was 8 minutes (interquartile range 6–11) compared with 13 minutes (interquartile range 8–17) for ICC. At least one adenoma was detected during the initial NBI pass in 28 patients (20.3%), and 42 patients (30.4%) had at least one adenoma detected after both NBI and ICC (difference, 10.1%; 95% confidence interval, −0.1%–20.3%); this represents an increase of 50.0% of the adenoma detection rate. ICC detected additional adenomas in 25 patients (18.1%). DISCUSSION: Colonoscopy combining NBI and ICC detects more adenomas than third-generation NBI alone in patients with LS, respectively, 30.4% vs 20.3% (difference, 10.1%; 95% confidence interval, −0.1 to 20.3), thus failing the noninferiority assumption of NBI compared with combined NBI and ICC. Although less time consuming, colonoscopy using the third-generation NBI cannot be recommended to replace ICC in patients with LS.