Transanal endoscopic microsurgery after neoadjuvant radiochemotherapy for locally advanced extraperitoneal rectal cancer.

PURPOSE: The aim of this study is to provide a prospective analysis of post-operative and oncological outcomes in patients affected by locally advanced rectal cancer (LARC), who obtained a major/complete clinical response after pre-operative radio-chemotherapy (RCT) and were treated with local excision (LE) by trans-anal endoscopic microsurgery (TEM) to confirm a pathological complete response (pCR) after to neo-adjuvant RCT.

METHODS: All patients with LARC treated by pre-operative RCT and full-thickness LE by TEM (2000-2014) were included in the study. If the pathological analysis confirmed near complete or pCR, intensive follow up was proposed. If the pathological response was incomplete, a radical resection with TME was proposed. Post-operative (according to Clavien's classification), functional and long-term oncological outcome were analyzed.

RESULTS: 36 patients were treated by TEM. The median post-operative hospital stay was 5 days. The post-operative morbidity was 41.6% (no grade ≥3). At pathological analysis, 23 specimens were ypT0 TRG1, and 4 were ypT1 TRG2. In 9 cases (ypT>1 and/or TRG>2), radical surgery with TME was proposed but 3 refused it. Median follow-up was 68 months. One local recurrence and 4 distant metastases occurred. The 5-yr actuarial local control, overall survival and disease-free survival were 96.0%, 92.0% and 82.8%.

CONCLUSIONS: In case of major or complete clinical response of LARC after pre-operative RCT, LE by TEM can be used to confirm the pathological response. This avoids the necessity of radical surgery and, in our experience, this approach seems to guarantee oncological safety with the functional advantages of an organ-sparing procedure.