Trans-anal endoscopic microsurgery for non- adenomatous rectal lesions.

Background: Trans-anal endoscopic microsurgery (TEM) enables a good visualization of the surgical field and is considered the method of choice for excision of adenomas and early T1 rectal cancer. The rectum and retro-rectal space might be the origin of uncommon neoplasms, benign and aggressive, certain require radical trans-abdominal surgery, while others can be treated by a less aggressive approach. In this study we report outcomes in patients undergoing TEM for rare and non-adenomatous rectal and retro-rectal lesions over a period of 11 years.

Aim: To report outcomes in patients undergoing TEM for rare and non-adenomatous rectal and retro-rectal lesions over a period of 11 years.

Methods: Between January 2008 to December 2019 a retrospective analysis was completed for all patients who underwent TEM for non-adenomatous rectal lesion or retro-rectal mass in our institution. Patients were discharged once diet was well tolerated and no complications were identified. They were evaluated at 3 wk post operatively, then at 3-mo intervals for the first 2 years and every 6 mo depending on the nature of the final pathology. Clinical examination and rectoscopy were performed during each of the follow-up visits.

Results: Out of 198 patients who underwent TEM during the study period, 18 had non-adenomatous rectal or retro-rectal lesions. Mean age was 47 years. The mean size of the lesions was 2.9 mm, with a mean distance from the anal margin of 7.9 cm. Mean surgical time was 97.8 min. There were no intra-operative neither late post-operative complications. Mean length of stay was 2.5 d. Mean patient follow-up duration was 42 mo.

Conclusion: TEM allows for reduced morbidity given its minimally invasive nature. Surgeons should be familiar with the technique but careful patient selection should be considered. It can be used safely for uncommon rectal and selected retro-rectal lesions without compromising outcomes. We believe that it should be reasonably considered as one of the surgical methods when treating rare lesions.