INTRODUCTION: The detection rate of proximal sessile serrated lesion (PSSLDR) is linked to the incidence and mortality of colorectal cancer. However, research on second forward view (SFV) examinations for PSSLDR remains limited. This first randomized controlled trial assessed the impact of the proximal SFV on the PSSLDR. METHODS: Patients were randomized into 2 groups during proximal colonoscopy: standard colonoscopy (SC) and SFV. The SC group underwent a standard examination, whereas the SFV group underwent a second examination of the proximal colon (cecum to splenic flexure). The primary outcome was PSSLDR, with secondary outcomes, including the proximal polyp detection rate (PPDR), proximal adenoma detection rate (PADR), and lesion miss rate, compared between the 2 groups. RESULTS: Among 246 patients (SC = 124
SFV = 122), SFV significantly improved the PSSLDR by 7.4% compared with SC (9.8% vs 2.4%, P = 0.017). SFV increased the PPDR by 20.2% (55.7% vs 35.5%, P = 0.002) and PADR by 12.7% (37.7% vs 25%, P = 0.039). Multivariate analysis revealed that sessile serrated lesions (odds ratio [OR] = 7.70, 95% confidence interval [CI] [1.58, 37.59]), inflammatory polyps (OR = 4.24, 95% CI [1.73, 10.39]), and lesion size (OR = 0.76, 95% CI [0.60, 0.96]) were associated with proximal missed lesions. The overall polyp miss rate was 52.9%, with miss rates of 61.0% for polyps <
5 mm, 80% for sessile serrated lesions, and 42.2% for adenomas. Furthermore, 12.3% of patients experienced changes in surveillance intervals from SFV examination. DISCUSSION: SFV examination of the proximal colon significantly improved the PSSLDR by 7.4%, PPDR by 20.2%, and PADR by 12.7%, while shortening the detection interval by 12.3%, making it a valuable and cost-effective addition to routine colonoscopy.