Colon and Rectal Cancer show similar survival in Advanced Early Onset Colorectal Cancer

Objective: This study aimed to compare clinicopathological characteristics and survival outcomes between colon and rectal primaries in a young, advanced-stage cohort. Background : The rising incidence of early-onset colorectal cancer necessitates a clearer understanding of its clinical behaviour. Most studies group colon and rectal cancers, but they have different entities. The comparative prognosis in young patients with advanced disease remains undefined. Method : A retrospective cohort study was conducted of 162 patients under 50 with stage III-IV colorectal cancer treated at a single center (2018-2023), categorized into colon (n=82) and rectal (n=80) groups. Clinicopathological data, treatment patterns, and survival outcomes were analyzed using Kaplan-Meier estimates, propensity score matching, and multivariable Cox regression. Results : The cohorts exhibited distinct clinical presentations: rectal cancer patients had more hematochezia (60% vs. 25.6%, p<0.001), while colon cancer patients presented with more abdominal pain (59.8% vs. 15%, p<0.001). Left colon dominated in colon group, whereas low rectum succeeded in the rectal group. Treatment differed significantly, with rectal group receiving more neoadjuvant therapy (27.5% vs. 8.5%, p=0.002). Though unadjusted analysis showed no significant difference in DFS (p=0.18) or OS (p=0.32), after propensity score matching, survival curves remained congruent. On multivariable analysis, tumour location was not an independent predictor of DFS (HR=1.15, p=0.56) or OS (HR=1.39, p=0.16), while advanced stage and synchronous metastasis were. Conclusion: In young patients with advanced colorectal cancer, tumour location does not independently predict survival. Despite different clinical presentations and treatment pathways, prognosis appears driven by factors like disease stage and biology rather than anatomical location.