Impact of chemotherapy-related prognostic factors on long-term survival in patients with stage III colorectal cancer after curative resection

This retrospective study evaluated the prognostic factors of chemotherapy in stage III colorectal cancer after curative resection. From 1996 to 2001, 1,054 patients with primary single colorectal cancer underwent curative resection. Seven hundred sixteen patients received various 5-fluorouracil (FU)-based adjuvant chemotherapy regimens, including oral and intravenous treatments. The chemotherapy-related parameters examined included therapeutic duration, frequency, route of administration, composition of combination therapies, and postoperative time interval from the operation to the start of chemotherapy. The therapeutic duration and postoperative time interval of starting therapy were independent prognostic factors, in addition to clinicopathological factors. The 8-year cancer-specific/overall survival rates in patients who received chemotherapy for > 4 months (63.0/58.6%) were significantly higher than the rates in patients who received no chemotherapy (56.7/37.7%, P < 0.01) and those who remained on chemotherapy for 1-4 months (49.4/41.9%, P < 0.05). The 8-year cancer-specific/overall survival rates in patients who waited 1-5 weeks after surgery to receive chemotherapy (62.9/58.5%) were significantly higher versus rates in those who did not receive chemotherapy (56.7/37.7%) and those who did not receive chemotherapy until > 5 weeks after surgery (52.3/45.9%) (both P < 0.05). Survival rates did not differ between patients who did not undergo chemotherapy, those for whom chemotherapy lasted 1-4 months, and patients who did not receive chemotherapy until > 5 weeks after surgery. The appropriate duration of therapy and early chemotherapy after surgery were 2 of the most important factors in eradicating occult cancer and effecting long-term survival benefits in patients with stage III colorectal cancer.