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.