Early rectal cancer treated by endoscopic submucosal dissection (ESD), endoscopic mucosal resection (EMR) or transanal endoscopic microsurgery (TEM)

Abstract

Rectal cancer is still a major cause of death. Early diagnosis allows diagnosis and treatment of the tumor at an early stage and it may improve prognosis. Early rectal cancer (ERC) is defined as an adenocarcinoma that involves rectal wall up to the submucosa, many effort have been spent to identify among ERC the lesions with a risk of lymph node metastases near to 0 in order to select cases amenable of local excision that is burdened by lower morbidity and mortality related to surgical procedure. A review of literature has been made to evaluate available stadiative methods in case of suspected ERC, indications of local excision and techniques of resection that allows perform local excision. When an early lesion is suspected endorectal echoendoscopy has to be performed to evaluate the depth of rectal wall involvement (T stadiation). Owing to relatively low correspondence between preoperative and postoperative stadiation (about 60%) local excision, when indicated, should achieve en bloc excision in order to obtain a correct stadiation and limitate further surgery for oncological reasons. Kikuchi and Kudo classification and histopathological characteristics allows to define tumors with lymph node metastases rate near to 0 and amenable of local excision. Endoscopic mucosal resection (EMR) allows en bloc resection of lesion inferior of 20 mm in diameter (about 50% of en bloc resection rate for lesions greater than 20 mm), so it is indicated for lesion suspected to be benign and inferior to 20 mm in diameter. Otherwise transanal endoscopic microsurgery (TEM) has demonstrate higher en bloc (99% vs. 89%) and R0 (89% vs. 74%) resection rate with regard to endoscopic submucosal dissection (ESD) and lower necessity of further surgery for oncological reasons (2% vs. 9%) so it is indicated for local excision of large colorectal lesion when available.