Local excision with transanal endoscopic microsurgery (TEM) after endoscopic R1/R2-polypectomy of pT1 "low-risk" carcinomas of the rectum

The transanal endoscopic microsurgery (TEM) is an adequate method for the local full-thickness excision of large rectum polyps and pT1 "low-risk" rectal carcinomas. We studied prospectively the relevance of this surgical technique concerning complete tumour excision after R1/R2-polypectomy of malignant rectal polyps. 16 patients with pT1 "low-risk" rectal carcinoma and macroscopic (R2) or microscopic (R1) incomplete endoscopic polypectomy were locally resected by TEM. In 12 patients (75 %) no residual tumour was found. In the remaining four cases (25 %), one adenoma with high-grade atypia, two pT1 "low-risk" carcinomas and one tumour infiltration in the mesorectal fat were diagnosed. The patient with the mesorectal infiltration was immediately operated on with radical resection. No further tumour cells were found in this specimen. The median follow-up was 21 months. One patient with a pT1 "low-risk" carcinoma developed a local recurrence and a single hepatic metastasis in the left liver lobe after TEM. Both were completely resected. Currently, all patients are living without evidence of tumour recurrence. Transanal endoscopic microsurgery is a suitable method for the treatment of pT1 "low-risk" rectal carcinomas after incomplete endoscopic polypectomy. In cases of a "high-risk" tumour or deeper tumour infiltration (pT> 1) after TEM radical resection must be carried out.