Bipolar underwater EMR for large colorectal polyps

Introduction The combination of underwater and bipolar is expected to be ideal for safe colorectal EMR (BUEMR). So far, no clinical trial have investigated the use of BUEMR for large colonic polyps with size 20 mm or larger (LCPs). We intoduce BUEMR for LCPs through videos and clarify its feasibility.
Methods We used a 26mm-sized hexagonal-shaped Dragonare-S (Zeon Medical, Japan) in all cases.
Results 12 cases with median lesion size 20 mm (range: 20-40) were included. Nine lesions (75%) was located in the right side colon. Half of the lesions were LST including 5 LSTNG. En bloc resection was achieved in 9 (75%) cases. No adverse events were observed. Histopathological diagnoses included 3 sessile serrated lesions, 5 low grade adenoma, 1 Tis, and 3 T1b lesions. In pT1b lesions, resection was all intended as a total excision biopsy, and endoscopic R0 were obtained in all cases. In 2 of them, pathological R0 was not obtained as an unclear vertical margin in both case. Additional surgery were performed for them. In another T1b case, R0 was obtained without other risk factor than invasion depth, and the patient denied additional surgery. In all piecemeal EMR cases, scope control was difficult and resulted in en bloc failure.
Conclusion: BUEMR for LCPs may be safe but R0 resection rate should be improved. It also potentially may serve as a total excision biopsy for lesions suspected submucosal invasion.