Prognosis of early-onset vs. late-onset stage II/III colorectal cancer patients with adjuvant chemotherapy: a multicenter propensity score matched study

Background Colorectal cancer (CRC) is a major global health concern, with a rising incidence in young individuals. Early-onset CRC displays unique clinicopathological and molecular characteristics, necessitating a closer examination of prognosis, particularly in the context of adjuvant chemotherapy. This study aimed to investigate the prognosis of early-onset CRC patients (< 50 years) diagnosed at stage II/III compared to older counterparts, utilizing propensity score matching to minimize heterogeneity. Methods A retrospective analysis of 3324 stage II/III CRC patients aged < 70 years was conducted, focusing on age-based subgroups (< 50 vs. >= 50 years). Propensity score matching balanced clinical characteristics. Relapse-free survival (RFS) and overall survival (OS) were analyzed. Results In stage II CRC, age of onset did not impact prognosis after adjuvant chemotherapy, with no significant differences in RFS (5-year RFS rates: 80% in both groups, p = 0.98) and OS (5-year OS rates: 96% vs. 92%, p = 0.17). In stage III, a trend suggested slightly poorer OS in patients aged < 50 years than those >= 50 years (5-year OS rates: 85% vs. 88%, p = 0.077). However, in a propensity score-matched cohort, age-dependent differences were attenuated (5-year OS rates: 85% vs. 88%, p = 0.32). Conclusion In the context of stage II/III CRC patients receiving adjuvant chemotherapy, age was not an independent predictor of prognosis. Age alone should not be the sole factor guiding treatment decisions.