Long-term outcomes in patients with locally advanced rectal cancer treated with preoperative chemoradiation followed by curative surgical resection.

OBJECTIVE: To determine the oncologic outcomes and clinical factors affecting survival in patients with locally advanced rectal cancer who underwent preoperative chemoradiotherapy (CRT) followed by curative surgical resection.
METHODS: We retrospectively analyzed outcomes in 581 patients who underwent preoperative CRT for advanced rectal cancer (T3/4 or node positive) followed by curative resection. All patients received preoperative radiation to the entire pelvis, at a total dose of 45-50.4 Gy in 20-25 fractions for 4-5 weeks, and 569 (97.9%) patients received concurrent chemotherapy with a 5-FU based agent. All patients underwent a curative proctectomy, including total mesorectal excision, a median 6 weeks later, and 432 (74.4%) patients underwent sphincter-saving surgery. Oncologic outcomes, including survival and recurrence, were evaluated according to pathologic parameters, and factors affecting survival were investigated.
RESULTS: The 5-year disease-free and overall survival rates were 72.4% and 77.8%, respectively. Eighty-nine patients (15.3%) had a pathologic complete response. Multivariate analysis showed that ypN category independently affected 5-year overall survival rates (ypN0 88.0%; ypN1 55.1%; ypN2 47.1%; P < 0.001). Factors independently affecting 5-year disease-free survival (DFS) rates included ypN category (ypN0 84.5%; ypN1 44.2%; ypN2 34.9%; P < 0.001), tumor regression grade (TRG1 52.9%; TRG2 72.0%; TRG3 86.7%; TRG4 86.8%; P = 0.004) and surgical method (sphincter-saving 76.3%; sphincter sacrificing 61.7%; P = 0.005).
CONCLUSION: Less advanced pathologic N-stage is a significantly favorable prognostic factor for disease-free and overall survival, with good response and sphincter saving surgery benefiting DFS.