Local Excision: Transanal Endoscopic Microsurgery and Transanal Minimally Invasive Surgery

Transanal endoscopic microsurgery (TEM) and transanal minimally invasive surgery (TAMIS) are minimally invasive approaches developed to facilitate the local excision of rectal lesions, collectively known as transanal endoscopic surgery (TES). TEM was originally designed to perform submucosal or full-thickness local resection of rectal adenomas, but its application has since expanded to include the curative resection of carefully selected early-stage rectal cancer. In this chapter, current indications and contraindications for TES in the treatment of rectal cancer will be reviewed, in addition to patient selection, preoperative preparation, and perioperative considerations. Surgical techniques, tips and tricks, and pitfalls associated with TES will also be discussed, as well as the published outcomes of this approach with respect to morbidity, functional results, and short- and long-term oncologic outcomes relative to conventional radical resection with total mesorectal excision (TME). Finally, current obstacles to routine use and wider adoption of TES in the management of carefully selected rectal cancer cases will be addressed, including the challenges of procedural costs and training.