Prognostic factors for 5 year relapse-free survivors following curative resection for stage II/III colorectal cancer.

[PURPOSE] With an increasing number of individuals surviving colorectal cancer (CRC), it is important to identify prognostic factors to determine follow-up strategies beyond 5 years. This study investigated the clinical factors associated with the overall survival (OS), disease-specific survival (DSS), and non-disease-specific survival (NDSS) in survivors who remained relapse-free for 5 years following curative resection for stage II/III CRC.

[METHODS] Among 1536 patients who underwent curative resection for stage II/III CRC between 2003 and 2018, 881 who remained relapse-free for 5 years were included. The OS, DSS, and NDSS beyond 5 years were analyzed using univariate and multivariate methods.

[RESULTS] The mean age was 77.5 years, and 54.6% were male. During a median follow-up of 34 months beyond 5 years, 87 individuals died (5 disease-specific and 73 non-disease-specific). The 5 year OS, DSS, and NDSS rates were 92%, 99%, and 92%, respectively. Multivariate analysis identified age ≥ 80 years, serum carcinoembryonic antigen ≥ 5.0 ng/mL, anemia, mean corpuscular volume ≥ 100 fL, and red cell distribution width (RDW) ≥ 14.9% as independent predictors of a poor OS.

[CONCLUSIONS] Five clinical factors-age ≥ 80 years, elevated CEA level, anemia, macrocytosis, and a high RDW-were identified as independent prognostic indicators among 5 year relapse-free survivors after stage II/III CRC resection. These findings highlight the importance of individualized long-term follow-up strategies, even beyond 5 years after surgery.