Objective: To evaluate 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 (n=11) with colorectal cancer.
Methods: Full-thickness colorectal amputation by either simple transanal (7 dogs) or combined abdominal-transanal (4) pull-through technique.
Results: Adenocarcinoma (8) and Tis (2) were removed with 3-6 cm of grossly normal tissue, cranial and caudal to the tumor, 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), rectal stricture (3), and long-term fecal incontinence (1). Postoperative recurrence and metastatic rates for adenocarcinoma were 18.2% and 0%, respectively. 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 for en bloc resection of colorectal neoplasia. A combined abdominal-transanal approach should be reserved for tumors extending from the mid-cranial region of the rectum to the descending colon.