Transanal endoscopic microsurgery: indications, tips and long-term results. A single center experience.

Background: Transanal endoscopic microsurgery (TEM) was introduced to combine the curativeness of full thickness excision with minimum morbidity, while traditional rectal surgery is burdened by high morbidity and mortality rates. However, while it is still a matter of considerable debate whether local excision is an adequate approach for curative resection of rectal cancer, new minimally invasive operative techniques have been introduced. The purpose of this paper was to show the indications, the tips and long term results of this technique through the review of the largest single-center database available to date. The showed results derived from the single center experience of the Clinica Chirurgica of Polytechnic University of Marche.

Methods: We retrospectively reviewed a 25-year database from May 1992 to May 2017. We divided the patients into three different groups of patients according to the preoperative diagnosis: rectal cancers, adenomas and other rectal lesions. Rectal adenomas were divided into two groups according to their diameter (> or <5 cm). Rectal cancer patients were divided into two groups according to the preoperative staging: early rectal cancer and irradiated rectal cancer.

Results: Among the 1324 patients who had rectal tumors excised with TEM at our institution, preoperative histology was rectal adenoma in 729 (55%) patients, adenocarcinoma in 536 (40.5%) patients and other lesions in the remaining 59 (4.4%) patients. 5 years overall survival (OS) and Recurrence free survival (RFS) were 93.3% and 98.6% for patients with rectal adenomas and 86.8% and 70.9% for patients with rectal cancer.

Conclusions: TEM can be a valid alternative for the treatment of both benign and malignant rectal lesions, further studies are needed to define more specific indications to justify the survival of this technique in the future.