Introduction: For colonic polyps containing foci of adenocarcinoma that are removed endoscopically with questionable margins or with unfavorable histologic features, segmental resection is recommended and can be performed with minimal morbidity. However, for a similar lesion of the distal rectum, radical resection involves a higher risk procedure such as very low anterior resection (LAR) or abdominoperineal resection. We report our experience with transanal re-excision (TAR) following endoscopic removal of rectal polyps containing adenocarcinoma.
Methods: From a prospective database, 21 patients were identified between 2000 and 2006 as having undergone full thickness TAR of the resection site following assumed complete gross endoscopic removal of a rectal polyp containing a focus of adenocarcinoma. All lesions demonstrated close, unclear or microscopically positive polypectomy margins. One patient with poor differentiation and 2 with lymphovascular invasion refused radical treatment (Table 1). Resected tissue was evaluated by standard sections and cytokeratin staining.
Results: The study population consisted of 11 men and 10 women with a median age of 60 years (range 39-86) and a median follow up of 24.8 months (range 1-62). Fifteen (71.4%) out of 21 patients demonstrated no evidence of residual tumor. Three patients were found to have residual adenoma, 2 patients were found to have residual foci of adenocarcinoma in the resected submucosa. Another patient was found to have no residual primary tumor but was found to have a positive lymph node in the specimen. This patient was treated with chemoradiation and LAR. The only morbidity reported was transient fecal incontinence in 6/21 patients. There were no peri-operative mortalities; 2 patients died from unrelated causes 10 and 16 months after operation. One patient developed a metachronous cancer 62 months after TAR and underwent APR for a T2N0 lesion. All other patients remain alive and free of disease at current follow up.
Conclusion: We conclude that in approximately one third of the patients described by our study, residual disease is identified following TAR. Given the relatively safety of this procedure, TAR should be considered for polyps harboring adenocarcinoma with unclear, close or positive margins and as an alternative to radical resection in selected patients.
Table 1. Histopathologic Profile

Histopathologic Parameters	n=21
Villous Tubulovillous Tubular	1353
SessilePedunculated	183
Differentiation Well-ModeratePoor	201
Lymphovascular Invasion	1
Margin:IndeterminateClose Microscopically Positive	983