Association Between ABO Blood Group and Survival in Early-Stage Colon Cancer: A Single-Center Retrospective Cohort Analysis

Background: ABO blood group antigens influence cell adhesion, inflammation, and metastatic processes, raising interest in their potential prognostic role in colorectal cancer. However, previous studies have reported inconsistent findings. This study evaluated the association between ABO blood group and overall survival (OS) in early-stage colon cancer patients undergoing curative surgery. Methods: This retrospective cohort included patients with pathologic stage II–III colon adenocarcinoma treated surgically between 2016 and 2024 at a single-center institution. Demographic, clinicopathological, and laboratory data—including ABO blood group—were collected. OS was analyzed using Kaplan–Meier and Log rank tests, and independent prognostic factors were assessed with multivariable Cox regression. Results: A total of 158 patients were included (median age 59 years; 63.3% male). Blood group distribution was: O (39.2%), A (38.6%), B (12.7%), and AB (9.5%). During a median follow-up of 31 months, 17.7% of patients died. Blood group B demonstrated significantly shorter OS compared with group O (log-rank p=0.014). In the multivariable analysis, only blood group B remained an independent predictor of worse OS (HR=1.99; 95% CI: 1.11– 3.60; p=0.022). Conclusion: Blood group B is independently associated with poorer survival in early-stage colon cancer. ABO typing may represent a potential adjunctive prognostic marker, warranting validation in larger prospective cohorts.