Submucosal resection via a transanal approach for treatment of epithelial rectal tumors – a multicenter study

Objective: To report complications and long-term outcomes after submucosal resections of benign and malignant epithelial rectal masses. Study design: Retrospective multicentric study. Sample population: Medical records of 93 dogs at 7 referral hospitals. Methods: Records were reviewed for surgical time, diagnosis, margins, complications, and recurrences. Survival of dogs was evaluated based on tumor types, categorized as benign, carcinoma in situ, and carcinoma. The Kaplan- Meier survival curve and Cox proportional hazards analysis were used to determine the association of a range of variables with recurrence and survival time. Results: Duration of follow up was 708 days (range, 25-4383). Twenty-seven dogs (29%) developed complications. Recurrence was identified in 20/93 (21%), with 12/20 recurrent masses treated with repeat submucosal resection. Median survival was not reached in any group. The 1-,2-, 5-year survival rates for carcinomas were 95%, 89%, and 73% respectively. However, overall survival was longer for benign tumors than carcinomas (P = .001). Recurrence was more likely when complications (P = .032) or incomplete margins (P = .023) were present. Recurrence was associated with an increased risk of death (P = .046). Conclusion: Submucosal resection of both benign and malignant rectal masses was associated with a low rate of severe complications and prolonged survival in the 93 dogs described here. Clinical significance: Submucosal resection is a suitable technique for resection of selected rectal masses.