evaluation of the association of blood group type with tumor location, polyp type, and colorectal cancer risk: a case-control study

Background: colorectal cancer (cc) is one of the most important causes of death due to cancer in the world. the association of blood groups with cc in many races has been reported in previous studies. so far, no study has evaluated the relationship between blood group type, tumor location, and polyp type. objectives: this study aimed at evaluating the association of the abo blood group and cc, tumor location, and polyp type. methods: in this case-control study, 802 subjects (401 cases and 401 controls), who underwent surgery at our medical centers between 2014 and 2021, were included. the case group was selected from the hospital records of patients with cc, and the controls were selected from non-cancer patients who were admitted to the same centers for reasons other than cancer. patients’ demographic characteristics and clinical and pathology findings were extracted from the medical profile, and blood group information was extracted from the blood bank. multivariate logistic regression analysis was used for the predictive variables of cc. results: the risk of cc in patients with blood type a was significantly higher than non-a. while the risk of developing cc in patients with blood type o was significantly lower than non-o o. the risk of developing neoplastic polyps was significantly higher in patients with blood type a compared to non-a. the results of multivariate analysis showed that abo blood type a (or adju: 1.66) and o (or adju: 0.78) and neoplastic polyp type (or adju: 1.36) were associated with cc. conclusions: the results of this study showed that abo blood group type was significantly related to cc and polyp type.