Relationship Between ABO Blood Group and the Risk of Colorectal Cancer: A Retrospective Multicenter Study.

Background:Colorectal cancer (CRC) is the fourth deadliest cancer, with approximately 900,000 deaths annually. CRC is a multifactorial disease in which a set of factors, including environmental, hereditary, and genetic factors, are integrated into cancer development. Studies have suggested an association between hereditary antigens in the human blood group system and the risk of different cancers. This study aimed to evaluate the relationship between blood groups and CRC risk. Methods:A record-based retrospective study was performed between January 2017 and August 2021. This study targeted patients diagnosed with CRC during the study period. Data of patients who agreed to participate were collected using a pre-structured checklist. The extracted data included patients' demographic blood groups and risk factors, including history of inflammatory bowel disease or CRC. Results:A total of 199 patients, aged 22 to 96 years (mean age: 61.6 ± 14.7 years), were included. The blood groups of 101 (50.8%), 59 (29.6%), 26 (13.1%), and 13 (6.5%) patients were O, A, B, and AB, respectively. Colon cancer was the most frequently reported cancer (155/199, 77.9%) across all blood groups and showed the highest frequency among patients with blood group O (74/155, 47.7%), without statistical significance (P = 0.111). Conclusion:Our study showed a statistically significant relationship between AB and non-O blood types and colon cancer compared to the O blood group.