Objective Adjuvant Chemotherapy Trial of TS-1 for Colon Cancer (ACTS-CC), a randomised phase III trial, demonstrated that adjuvant therapy with S-1 for stage III colon cancer was non-inferior in 3-year disease-free survival (DFS) to that of tegafur-uracil plus leucovorin (UFT/LV). We updated DFS and overall survival (OS) and performed T x N subset analysis
Methods A total of 1518 patients with curatively resected stage III colon cancer were randomly assigned to receive S-1 (80–120 mg/day on days 1–28 every 42 days, four courses) or UFT/LV (UFT: 300–600 mg/day and LV: 75 mg/day on days 1–28 every 35 days, five courses)
Results The 5-year DFS rates of the S-1 and UFT/LV group were 70.2 % and 66.9 %, respectively (HR 0.88; 95% CI 0.74 to 1.06; p=0.177), and non-inferiority of DFS was reconfirmed with a median of 63.5-month follow-up. The similarity of OS was also confirmed (HR 0.92; 95% CI 0.72 to 1.17; p=0.488); 5-year OS rates of the S-1 and UFT/LV group were 86.0 % and 84.4 %, respectively. No significant interactions were identified between the major baseline characteristics and DFS of the S-1 and UFT/LV groups, except for histological type; S-1 was more favourable in patients with poorly differentiated adenocarcinoma. Patient outcomes were well separated by TNM-substages (IIIA/IIIB/IIIC). With the patients divided into 20 subsets by T and N factors, the DFS and OS rates of T3 and N1 subset, which accounted for 62 % of stage IIIB patients and 44 % of all studied subjects, were significantly better than those of the other subsets in stage IIIB and similar to those of stage IIIA.
Conclusions Adjuvant therapy of S-1 for stage III colon cancer was reconfirmed to be non-inferior in DFS to those of UFT/LV after long follow-up. No difference in OS was also demonstrated. T3N1 patients might be considered separately from other patients included in stage IIIB because of its favourable outcome.
Trial registration number NCT00660894.
- colon cancer
- adjuvant chemotherapy
- tegafur-uracil (UFT)
- TNM classification
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Contributors MI and KS contributed to the conception and design of the study. TK, MI, EN and KS contributed to data analysis and interpretation. TK, MY, TI, YN, AS, AT, ES, HS, YT, AM, HO, HH, MM, TY, MN and YM contributed to collection and assembly of data. All authors contributed to manuscript writing and final approval if the manuscript.
Funding This work was supported by the Foundation for Biomedical Research and Innovation at Kobe, Translational Research Center for Medical Innovation, under the funding contract with Taiho Pharmaceutical Co. Ltd., Japan.
Competing interests MI has received honoraria from Taiho Pharmaceutical Co. Ltd., and Merck Serono Co. Ltd.; research funding from Taiho and Yakult Honsha Co. Ltd. KS received honoraria and research funding from Taiho Pharmaceutical Co. Ltd. and Chugai Pharmaceutical Co. Ltd. All remaining authors have declared no conflicts of interest.
Patient consent Not required.
Ethics approval Intestinal Board of Tokyo Medical and Dental University Medical Hospital.
Provenance and peer review Not commissioned; externally peer reviewed.
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