Abstract 415P
Background
We reported that data from the ACHIEVE trial revealed that post-operative serum CEA was strongly prognostic of disease-free survival (DFS) for stage III colon cancer (ASCO2020). This post-hoc study aimed to clarify the prognostic effect of postoperative CEA for high-risk stage II colon cancer.
Methods
The ACHIEVE-2 trial, as part of the IDEA Collaboration, was a multicenter trial to randomize patients with high-risk stage II colon cancer to either 3 versus 6 months of adjuvant FOLFOX/CAPOX. The eligibility criteria in the trial included postoperative serum CEA value of <10 ng/ml at registration.
Results
Of 514 patients analyzed, median CEA value was 1.9 (range, 0.5–9.9). 48 (9%) patients had a CEA of ≥5.0 ng/ml and 466 (91%) had a value of <5.0. 3-year DFS was 86% in the ≥5.0 group and 88% in the <5.0 group, with a hazard ratio (HR; reference, <5.0) of 1.27 (95%CI, 0.58–2.79). Multivariate analysis showed that CEA was not an independent prognostic factor (P=0.5117). However, in the subgroup of patients with T3N0 tumor (n=330), 3-year DFS in the ≥5.0 group was significantly lower than that in the <5.0 group (84% vs 95%) with a HR of 2.83 (1.04–7.75), whereas in patients with T4N0 tumor (n=184), this relationship was opposite; 3-year DFSs in the ≥5.0 and <5.0 groups were 88% and 77%, respectively, with a HR of 0.51 (0.12–2.12). The interaction test for T-factor (T3 vs T4) by CEA (≥5.0 vs <5.0) was significant (P=0.0479).
Conclusions
Postoperative CEA was prognostic in patients with T3N0 tumor, whereas this association did not hold in T4N0 tumor, suggesting that the characteristics of T4N0 tumor might have diluted the prognostic effect of CEA. Further analyses incorporating T4N0 tumor’s features, such as microsatellite status, would be warranted.
Clinical trial identification
UMIN000013036.
Editorial acknowledgement
Legal entity responsible for the study
Japanese Foundation for Multidisciplinary Treatment of Cancer.
Funding
Yakult Honsha Co, Ltd.
Disclosure
M. Kotaka: Honoraria (self): Chugai Pharmaceutical; Honoraria (self): Yakult Honsha; Honoraria (self): Takeda Pharmaceutical. A. Makiyama: Advisory/Consultancy, Speaker Bureau/Expert testimony: Eli lilly; Speaker Bureau/Expert testimony: Chugai Pharma; Speaker Bureau/Expert testimony: Takeda Pharmaceutical. K. Shitara: Advisory/Consultancy, Research grant/Funding (institution): Astellas; Advisory/Consultancy, Research grant/Funding (institution): Lilly; Advisory/Consultancy: Bristol-Myers Squibb; Advisory/Consultancy: Takeda; Advisory/Consultancy: Pfizer; Advisory/Consultancy, Research grant/Funding (institution): Ono; Advisory/Consultancy, Research grant/Funding (institution): MSD; Advisory/Consultancy, Research grant/Funding (institution): Taiho; Advisory/Consultancy, Research grant/Funding (institution): Chugai; Honoraria (self), Advisory/Consultancy: Novartis; Honoraria (self), Advisory/Consultancy: AbbVie; Advisory/Consultancy: GlaxoSmithKline; Research grant/Funding (institution): Sumoitomo Dainippon; Research grant/Funding (institution): Daiichi Sankyo; Research grant/Funding (institution): Medi Science; Honoraria (self): Yakult. E. Oki: Speaker Bureau/Expert testimony: Chugai Pharm; Speaker Bureau/Expert testimony: Yakult Honsha; Speaker Bureau/Expert testimony: Taiho Pharm; Speaker Bureau/Expert testimony: Eli Lilly; Speaker Bureau/Expert testimony: Bayer; Speaker Bureau/Expert testimony: Merck Biopharm; Speaker Bureau/Expert testimony: Takeda pharm. T. Yamanaka: Honoraria (self), Research grant/Funding (institution): Chugai Pharma; Honoraria (self), Research grant/Funding (institution): Bayer. K. Yamazaki: Honoraria (self): Yakult Honsha; Honoraria (self): Chugai Pharma. A. Ohtsu: Honoraria (self), Research grant/Funding (institution): BMS; Honoraria (self): Ono Pharma; Honoraria (self): Taiho; Honoraria (self): Chugai. T. Yoshino: Research grant/Funding (institution): Novartis Pharma K.K; Research grant/Funding (institution): MSD K.K; Research grant/Funding (institution): Sumitomo Dainippon Pharma Co., Ltd.; Research grant/Funding (institution): Chugai Pharmaceutical Co., Ltd.; Research grant/Funding (institution): Sanofi K.K.; Research grant/Funding (institution): Daiichi Sankyo Company, Limited; Research grant/Funding (institution): Parexel International Inc.; Research grant/Funding (institution): Ono Pharmaceutical Co., Ltd.; Research grant/Funding (institution): GlaxoSmithKline K.K.. All other authors have declared no conflicts of interest.