Outcome standards for an organ preservation strategy in stage II and III rectal adenocarcinoma after neoadjuvant chemoradiation.

BACKGROUND: Neoadjuvant chemoradiotherapy is the standard of care for patients with locally advanced mid and distal rectal cancer. Tumor regression is variable, and this study was designed to evaluate the pathological response and impact on long-term disease control in responders and nonresponders.
METHODS: A total of 303 consecutive patients with cStage II and III mid and distal rectal adenocarcinoma were identified. The mean age was 64 years and 63% were men. Patients received neoadjuvant chemoradiotherapy (45 Gy) with a continuous infusion of 5-fluorouracil. Total mesorectal excision (TME) was performed after an interval of 6-8 weeks. Tumors were stratified as responders (ypT0 or ypT1) and nonresponders (≥ypT3). All ypT2 were separately categorized.
RESULTS: Tumors of 84 patients were classified as responders (27.5%) versus nonresponders in 144 patients (47.5%). Pathological tumor stage was ypT2 in 75 patients (25%). After a median follow-up of 55 months, the 5-year cancer-specific survival rate was 98% and the disease-free survival rate was 91% in responders versus 82% (P < 0.0025) and 60% (P < 0.0001), respectively, for the nonresponders.
CONCLUSIONS: After neoadjuvant chemoradiotherapy and TME surgery for locally advanced rectal cancer and complete or near-complete pathological tumor response oncological outcome is very good. These results set the standards for a rectum-sparing strategy.