Clinicopathologic features and prognostic factors in early- versus late-onset colorectal cancer: a stage-stratified retrospective surgical cohort from the Mekong Delta, Vietnam.

BACKGROUND: Early-onset colorectal cancer (EOCRC), defined as diagnosis before 50 years of age, has increased in incidence globally, but its clinicopathologic profile and prognostic significance remain incompletely characterized, particularly in Southeast Asian populations with limited access to organized screening. AIMS: To compare clinicopathologic characteristics and survival outcomes between EOCRC and late-onset colorectal cancer (LOCRC) following curative resection, and to identify independent prognostic determinants in a regional Vietnamese surgical cohort. METHODS: This retrospective cohort study included 486 patients with stage I-III colorectal adenocarcinoma who underwent curative laparoscopic resection at a tertiary center in the Mekong Delta between 2016 and 2022. RESULTS: EOCRC (184 patients, 37.9%) was associated with higher rates of poor differentiation, mucinous or signet-ring cell histology, lymphovascular invasion, and perineural invasion compared with LOCRC (all p<0.05). Overall survival (OS), cancer-specific survival (CSS), and recurrence-free survival (RFS) did not differ significantly between groups. In the overall cohort (log-rank p=0.72, 0.15, and 0.96, respectively). On multivariable analysis, postoperative complications were the dominant independent prognostic factor for OS (hazard ratio [HZ] 8.28; 95% confidence interval [CI] 4.87-14.09) and RFS (HZ 4.81; 95%CI 3.03-7.65), whereas age at onset was not independently associated with either outcome. Stage-stratified curves suggested a less favorable survival pattern among patients with stage III EOCRC, particularly for CSS and RFS. CONCLUSIONS: Despite a more aggressive histopathologic profile, EOCRC showed comparable survival to LOCRC in the overall cohort. Stage-stratified curves suggested a less favorable survival pattern among patients with stage III EOCRC, while postoperative complications represented the dominant modifiable determinant of outcome.