Giant adenomas of the rectum: complete resection by transanal endoscopic microsurgery (TEM)

Large sessile adenomas of the rectum, with a diameter greater than 5 cm, have a high risk to undergo malignant transformation. Transanal endoscopic microsurgery (TEM) offers an alternative operation method to low-anterior rectum resection in this potentially benign tumor situation.

We retrospectively investigated patients with giant adenomas of the rectum (>5 cm) who were treated by TEM over the last 10 years. A total of 33 patients met the criteria and were analyzed for postoperative complications, histology, and incidence of occult adenocarcinoma; residual tumor status; and tumor recurrence.

Partial suture-line insufficiency (n=5, 15%) was the major postoperative complication, but could be managed conservatively in four cases. The residual adenoma status was 18% (n=6), especially in patients with tumors sizes more than 30 cm². In case of adenoma recurrence (n=4, 12%), a conventional transanal excision (Parks) was applicable, as these tumors were mostly located within the suture-line region of the lower rectum. Incidentally, five carcinomas were found in the specimens. In case of advanced tumors (1×pT2, 1×pT3), anterior rectum resection was carried out, whereas for the early tumors (2×pT1 low risk, 1×1 pTis), no further therapy was added. All patients (adenomas and carcinomas, n=33) were without recurrence during follow-up.

TEM is an alternative method for the resection of large benign rectal tumors located in the mid- and upper third of the rectum. The main postoperative complication is suture-line insufficiency, which generally heals by conservative treatment.