OBJECTIVETo investigate the clinical value of transanal endoscopic microsurgery (TEM) for rectal intraepithelial neoplasia (IN) and early rectal carcinoma.

METHODSFifteen patients with rectal tumor were selected to undergo local excision by TEM. The pre-operative diagnosis by biopsy and endoanal ultrasonography (EUS): rectal low-grade IN in 8 cases, high-grade IN in 4 and early rectal carcinoma in 3. The average distance of tumors from the anal verge was 7.2(4-15) cm. The average tumor size was 1.8(1-4) cm. The average proportion of the circumference of bowel lumen involved was 20%(10%-40%).

RESULTSAll the 15 rectal tumors were achieved complete excision (submucosal excision in 5, full-thickness excision in 10), and all the resection margins were clear. The average operating time was 57 (40-90) min. The average blood loss was 35 (10-60) ml. The average post-operative stay was 4.5 (2-9) d. The post-operative pathological diagnosis: rectal low-grade IN in 5 cases, high-grade IN in 6, early submucous invasive carcinoma (pT(1)) in 2, advanced carcinoma (pT(2)) in 2. The diagnostic accuracy of EUS in assessing invasive depth of rectal tumor was 86.7% (13/15). The average follow-up period of 15 patients was 6 (2-10) months. There was no local recurrence occurred.

CONCLUSIONTEM is an ideal minimally invasive procedure for the treatment of rectal IN and early rectal carcinoma, with excellent exposure and accurate excision, providing a high-quality tumor specimen for pathological staging. Pre-operative EUS is very important in selecting patients suitable for resection by TEM.