Transanal endoscopic microsurgery: exploring its indications and novel applications. A narrative review

Featuring some advantages of endoscopy and microsurgery, transanal endoscopic microsurgery (TEM) was first introduced in treating local early-stage rectal lesions in 1983. However, its applications to rectal surgery have remained virtually unchanged over the past 38 years. This review aims to describe some well-accepted indications for TEM and showcase other novel but successful applications. In this review, we conducted a thorough English literature review on the applications of transanal endoscopic microsurgery in the PubMed database. Published original articles, case reports, and letters from 1983 to 2020 were included. Retrieved articles were discussed and conclusions were made. The results showed that applications of TEM could be more flexible and extended, namely, TEM's niche applications in advanced rectal cancer after neoadjuvant chemoradiotherapy, neuroendocrine tumor, gastrointestinal stromal tumor, fistula, solitary rectal ulcer syndrome, benign stricture, and transanal total mesorectal excision are promising, while prospective studies are needed.