Monthly tegafur–uracil maintenance for increasing relapse-free survival in ypStage III rectal cancer patients after preoperative radiotherapy, radical resection, and 12 postoperative chemotherapy cycles: a retrospective study

Abstract Background Current advancements in neoadjuvant therapy and total mesorectal excision have engendered increased local control. However, the survival benefit of preoperative radiotherapy (RT; 5 × 5 Gy) in rectal cancer patients remains inadequate, primarily because of systemic recurrence. In this retrospective single-center study, the effects of monthly tegafur–uracil maintenance (≥6 cycles) after 12 fluorouracil-based adjuvant chemotherapy cycles on 3-year relapse-free survival (RFS) was estimated in ypStage III rectal cancer patients. Methods Of ypStage III rectal cancer patients who received preoperative RT (5 × 5 Gy) in January 2006–December 2015, those who had ypStage III cancer after preoperative radiation, radical resection, and postoperative chemotherapy were enrolled; excluded patients had ypStage I and II rectal cancer, had double cancer, had synchronous distant metastasis, had local excision, received preoperative chemoradiation, and were lost to follow-up within 1 year after cancer treatment. Included patients received either maintenance therapy or observation after postoperative chemotherapy. The primary endpoint was the effect of maintenance therapy on 3-year RFS. We set the median follow-up duration to be 69.7 (range, 15.4–148.3) months. Results Of 259 ypStage III rectal cancer patients, 102 (59 men and 43 women) were enrolled based on the inclusion criteria. The maintenance and observation groups comprised 55 and 57 patients, respectively (mean age = 62.2 and 65.7 years, respectively; p = 0.185). The 3-year RFS observed in the maintenance group (85.1%) was longer than that observed in the observation group (67.5%; p = 0.039). Multivariate analysis proved the following to be independent prognostic factors for RFS: higher metastatic lymph node ratio (LNR ≥0.3), tegafur–uracil maintenance (≥6 cycles), and lower rectal cancer (