EP486 - Outcomes of Endoscopic lntermuscular dissection Dissection (EID) versus Robotic Transanal Minimally Invasive Surgery (r-TAMIS) for Large Rectal Adenomas

Purpose/Background: Large rectal polyps potentially harbour early adenocarcinoma potential. En-bloc excision with sufficient margins is paramount towards organ preservation. We compare outcomes of two emergent local excision techniques r-TAMIS versus EID.

Methods/Interventions: Large flat rectal lesions measuring greater than 2 centimetres underwent either EID or r-TAMIS after their case was reviewed in our local MDT from July 2024 until September 2025. En-bloc resection rate, resection margins, recurrence, complications and length of stay were prospectively collected and retrospectively analysed.

Results/Outcomes: A total of 17 patients underwent either EID (9) versus r-TAMIS (8). Patient demographics and location in the rectum were similar in either group. Average maximal dimension of polyps were marginally larger in the r-TAMIS group (45 vs 38.33 mms). All patients in both groups bar 1 of 9 in the endoscopic group underwent an en-bloc and R0 resection. The incompletely resected polyp via ESD was found to be a poorly differentiated adenocarcinoma breached beyond the submucosal plane. There were no complications, recurrence on surveillance endoscopy in either group and there was no difference in mean length of stay of less than 1 day.

Conclusion/Discussion: In our early experience, both techniques were found to be safe and have similar results other than one involved margin in the EID cohort. Resource analysis of time and cost is essential towards establishment of optimal technique.