Transanal endoscopic microsurgery for giant polyps of the rectum

The potential for malignancy in rectal polyps increases with the size of the polyp, and unexpected malignancy is reported in up to 39 % of large rectal adenomas. Transanal endoscopic microsurgery (TEM) offers the possibility of an en bloc full-thickness excision for lesions in the rectum. We present our results with TEM in the removal of giant polyps equal or greater than 4 cm in diameter.

In the period between 1998 and 2012, TEM was performed in 39 patients with rectal polyps measuring at least 4 cm in diameter. Transrectal ultrasound and/or magnetic resonance imaging of the rectum was used when cancer was suspected.

The polyp was removed with en bloc full-thickness excision in 77 % (n = 30). The preoperative diagnosis was benign rectal adenoma in 89.7 % (n = 35). The median size of the polyps was 30 cm² (range 16–100 cm²). Postoperative complications included bleeding in 4 patients (10.3 %). Histological examination showed unexpected cancer in 4 patients (10.3 %). TEM was curative in 2 of these patients, and the other 2 underwent further surgery. Recurrences occurred in 10 patients (25.6 %) and consisted of 5 adenomas and 5 adenocarcinomas. In 5 patients, these recurrences were treated with endoscopic removal or re-TEM. The remaining 5 underwent total mesorectal excision and/or chemotherapy.

Full-thickness TEM provides a safe and efficient treatment for excision of giant polyps. In case of unexpected cancer, TEM can be curative. Local recurrence can be often treated with a second TEM procedure.