Clinicopathological characteristics and prognosis of early-onset colorectal cancer: a retrospective cohort study

Objective To investigate the clinical and pathological characteristics of patients with early-onset colorectal cancer (EOCRC) and to evaluate their impact on postoperative overall survival (OS) within the observed follow-up period. Methods Consecutive colorectal cancer patients who underwent radical surgery at Zhangzhou Affiliated Hospital of Fujian Medical University between 2017 and 2024 were included. Patients were categorised into EOCRC group (≤50 years), and late-onset colorectal cancer (LOCRC) group (>50 years) based on age at diagnosis. To reduce baseline confounding, 1:4 propensity score matching (PSM) was performed. Stratified survival analyses were conducted across different TNM staging levels. Results A total of 4,596 colorectal cancer patients were included, including 590 cases of EOCRC and 4,006 cases of LOCRC. Prior to PSM, EOCRC patients showed a higher proportion of females, lower ASA staging, increased prevalence of poorly differentiated tumours, mucinous adenocarcinoma/signet ring cell carcinoma, and dMMR status, alongside a relatively more advanced stage distribution. Median follow-up duration was 34.5 months. Both in the unmatched and matched cohorts, EOCRC patients demonstrated significantly superior OS compared to LOCRC patients. Multivariate Cox regression analysis demonstrated that EOCRC was an independent protective factor for OS both before (HR = 0.650, 95% CI 0.520–0.814) and after matching (HR = 0.641, 95% CI 0.509–0.809). Further stratified analysis by disease stage indicated that, among patients with stages I–IV disease, EOCRC demonstrated non-inferior OS outcomes compared with LOCRC, with the survival advantage being more pronounced in stage II and stage III patients. Conclusion In a large single-centre retrospective cohort, despite presenting with certain unfavourable clinical and pathological characteristics at diagnosis, patients with EOCRC demonstrated OS comparable to those with LOCRC, exhibiting superior survival trends in certain staging groups. Prognosis assessment and clinical management of colorectal cancer should not rely solely on age at onset, but rather involve comprehensive decision-making incorporating staging, pathological features, and the patient’s overall condition.