Intramucosal carcinoma of the rectum can be safely treated with transanal endoscopic microsurgery; clinical support of the revised Vienna classification.

AIM: The revised Vienna criteria were proposed for classifying rectal neoplasia and subsequent treatment strategies. Restaging intramucosal carcinoma to a non-invasive subgroup seems logical, but clinical support is lacking. In this study, we investigated whether distinction between intramucosal carcinomas (IMC) and rectal adenoma (RA) is of clinical relevance and whether these neoplasms can all be similarly and safely treated by transanal endoscopic microsurgery (TEM).

METHODS: All consecutive patients with IMC and RA, treated with TEM between 1996 and 2010 in tertiary referral centre for TEM were included. Long-term outcome of 88 IMC was compared to 356 pure rectal adenomas (RA). Local recurrence (LR) rate was the primary endpoint. Risk factors for LR were analysed.

RESULTS: LR was diagnosed in 7/88 patients (8.0 %) with IMC and in 33/356 patients with primary RA (9.3 %; p = 0.700) and LR-free survival did not differ (p = 0.438). Median time to recurrence was 10 months (IQR IMC 5-30; RA 6-16). Overall recurrence occurred mainly in the first 3 years (38/40; 95 %). None of the LR revealed malignancy on pathological evaluation. No differences could be found in complication rates (IMC 9 %; RA 13 %; p = 0.34). Metastases did not occur in either group. Independent risk factors for LR were irradical margins at final histopathology (HR 2.32; 95 % CI 1.17-4.59; p = 0.016) and more proximal tumours (HR 0.84; 95 % CI 0.77-0.92; P = <0.001).

CONCLUSION: In this study, IMC of the rectum and RA have similar recurrence rates. This supports the revised Vienna classification. Both entities can be safely treated with TEM.