Transanal Microsurgery TEM and TEO

Transanal endoscopic microsurgery (TEM) is a minimally invasive treatment that allows excision of large rectal neoplasms up to 20 cm from the anal verge, reducing the postoperative morbidity and mortality of conventional total mesorectal excision (TME). Compared to endoscopic technique like endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD), TEM seems to achieve better oncologic results, with similar complications rate. Even if preoperative staging actually presents many limitations, TEM indications have been extended in the last years. The present indications to TEM are represented by benign lesions unsuitable for endoscopic resection and early rectal cancers deepening no more than 1 mm in the submucosal space. The future researches are focused on the extension of indication of TEM to more advanced rectal cancers such preoperative neoadjuvant chemoradiotherapy and intraoperative lymph node mapping with sentinel node biopsy. An advancement in the preoperative staging will permit a case-specific treatment, leading to a significant minimization of the invasiveness of the treatment.