Transanal pull-through rectal amputation for the treatment of colorectal carcinoma in 11 dogs

Objective - To evaluate postoperative and oncologic outcome after transanal rectal pull-through amputation of single colorectal adenocarcinoma and in situ carcinoma (Tis) in dogs. Study design – Retrospective case series Animals - Dogs (11) with colorectal cancer. Methods – Full-thickness colorectal amputation by either simple transanal (7 dogs) or combined abdominal-transanal (4 dogs) pull-through technique. Results – Adenocarcinomas (8) and Tis (2) were removed with 3-6 cm of grossly normal tissue cranial and caudal, or in 1 Tis with 2 cm grossly normal tissue, cranial and caudal. Two dogs that had a combined abdominal-transanal approach died within 4 days. In the other dogs, postoperative complications included short-term tenesmus (6 dogs), rectal bleeding (11 dogs), rectal stricture (3 dogs), and long-term fecal incontinence (1). Postoperative recurrence and metastatic rates for adenocarcinoma were 18.2% and 0%, respectively. The median disease-free interval and survival time were not reached. Mean disease-free and overall survival times were 44.3 and 44.6 months (range 0-75 months), respectively. Conclusion - En bloc excision of colorectal Tis and adenocarcinoma may be followed by a long survival. Complications of the transanal approach are usually moderate and self-limiting, but complications are more common and severe when more extensive resections are performed through a combined abdominal-transanal approach. Clinical relevance – Transanal rectal pull-through amputation is suitable to en bloc resection of colorectal neoplasia. A combined abdominal-transanal approach should be reserved to tumors extending from mid-cranial region of the rectum to the descending colon.