Colorectal polyp size measurement comparing biopsy forceps with visual assessment during real-time colonoscopy: A prospective, multicenter, international study

BACKGROUNDColorectal polyp size is important for assigning appropriate surveillance intervals, but conventional visual assessment (VA) often results in size misclassification.The use of a biopsy forceps (BF) might improve polyp size assessment as suggested in current guidelines. AIMTo compare measurement performance of BF-assisted size measurement with VA during real-time colonoscopy. METHODSA prospective, multicenter, international study was conducted at 5 tertiary hospitals.Patients aged ≥ 18 years scheduled for screening, surveillance, or diagnostic colonoscopy were included.Polyps were measured during colonoscopy with VA, BF, and a laser system (reference standard) and then removed and sent for histopathological assessment.The primary outcome was inter-method agreement of BF and VA compared to laserbased size measurement.Secondary outcomes included inter-method agreement between BF and VA and size misclassification.Furthermore, clinical implications were explored. RESULTSAmong 110 patients, 276 polyps were detected, including 138 with successful reference laser-based measurements, of which 137 were analyzed.Moderate agreement was found for BF and VA compared to laser measurements (κ = 0.534 vs 0.514) with wide limits of agreement (± 3 mm), while almost perfect agreement (κ = 0.863) was observed between BF and VA.Both BF and VA underestimated polyp size by -0.16 mm and -0.11 mm, 4 / 32 underestimating around 14%-50% of > 5 mm and ≥ 10 mm polyps and overestimating approximately 2%-11% of ≤ 5 mm and < 10 mm polyps.Around 2% of patients were assigned an incorrect surveillance interval using BF and VA, and when implementing a resect-and-discard strategy, 11% of ≤ 5 mm polyps would have undergone histopathology and 14% of > 5 mm polyps would have been discarded. CONCLUSIONBF-assisted size measurement performs similarly to conventional VA, without improving precision or reducing size misclassification.Thus, BF can unlikely replace VA in routine colonoscopy, nor be recommended in clinical guidelines.