Long-term outcomes and prognostic factors of preoperative chemoradiotherapy with oral dihydropyrimidine dehydrogenase inhibitory fluoropyrimidines in patients with locally advanced rectal cancer

Abstract

Abstract Background The purpose of this study was to determine long-term outcomes and prognostic factors in patients with locally advanced rectal cancer who received preoperative chemoradiotherapy with oral dihydropyrimidine dehydrogenase (DPD)-inhibiting fluoropyrimidines. Methods Fifty-seven locally advanced rectal cancer patients who underwent preoperative chemoradiotherapy (CRT) with oral DPD-inhibitory fluoropyrimidines from 2006 to 2013 were retrospectively enrolled in this study. Patients with T3–T4 lower rectal cancer were irradiated once daily (2 Gy) with a total dose of 40 Gy, and chemotherapy was administered with tegafur-uracil (300 mg/m2/day) or S-1 (80 mg/m2/day) on radiation days. Total mesorectal excision was performed 6–8 weeks after the completion of radiotherapy. Results Pathologic complete response was observed in three patients (5.6%) with a pathologic response rate of 26.3%. Five-year overall survival was 77.8% and 5-year disease-free survival was 65.1%. Recurrence was observed in 20 patients (35.1%) and local recurrence in 9 patients (15.8%). Multivariate analysis of prognostic factors for overall survival identified pre-CRT lateral lymph node metastasis and circumferential resection margin as independent prognostic factors, and ypStage as an independent prognostic factor for disease-free survival. Conclusions Evaluation of lateral lymph node before CRT is useful in predicting prognosis in patients with locally advanced lower rectal cancer treated with preoperative chemoradiotherapy with oral DPD-inhibiting fluoropyrimidines, and surgical planning to ensure a 1-mm circumferential resection margin is important for improving prognosis.