From the Guidelines
Patients with Type A (ABO blood group) blood have an increased risk of developing gastric carcinoma primarily due to the higher affinity of Helicobacter pylori bacteria for type A blood group antigens, leading to more severe inflammation and damage to the stomach lining over time. This increased risk is supported by the fact that H. pylori infection is a major risk factor for gastric cancer, as noted in a 2022 study published in the Annual Review of Medicine 1. The study highlights that gastric cancer is an inflammation-induced cancer in which H. pylori infection both initiates and maintains mucosal inflammation.
The biological mechanisms underlying this increased risk include the ability of type A antigens on stomach cells to serve as binding sites for H. pylori bacteria, allowing for more effective adhesion and subsequent inflammation. Additionally, individuals with type A blood tend to have lower levels of stomach acid production, which may enable harmful bacteria to survive more easily in the stomach environment. Genetic associations between the ABO gene locus and genes that influence cancer development may also play a role.
Key points to consider include:
- The risk of gastric cancer depends on developing atrophic gastritis, which can be influenced by H. pylori infection 1.
- Eradication of H. pylori infection can halt the increase of risk and reduce the overall risk of gastric cancer 1.
- The natural history of gastric cancer risk is an exponential increase with age, emphasizing the importance of early screening and intervention.
- Regular screening may be beneficial for those with type A blood, especially if they have additional risk factors such as a family history of gastric cancer or H. pylori infection.
Overall, the increased risk of gastric carcinoma in individuals with type A blood highlights the importance of considering ABO blood group as a potential risk factor in the development of gastric cancer screening and prevention strategies.
From the Research
Association between ABO Blood Group and Gastric Cancer
- The ABO blood group system has been associated with the risk of gastric cancer, with individuals having blood type A showing an increased risk 2, 3, 4, 5, 6.
- Studies have consistently shown that individuals with blood type A have a higher risk of developing gastric cancer compared to those with other blood types 2, 4, 5, 6.
- The odds ratio for blood type A relative to other types was found to be 1.39 (95% CI: 1.12-1.73) for dysplasia and 1.28 (95% CI: 1.06-1.53) for intestinal metaplasia 2.
- A case-control study found that the risk of gastric cancer in blood group A was significantly higher than that in non-A groups (OR = 1.34; 95% CI 1.25-1.44) 5.
- A meta-analysis also found consistent evidence that gastric cancer risk in the blood A group was higher than that in the non-A groups (OR = 1.11; 95% CI 1.07-1.15) 5.
Possible Mechanisms
- The association between blood type A and gastric cancer may be related to the increased risk of Helicobacter pylori infection in individuals with blood type A 5.
- The proportion of H. pylori infection in blood group A individuals was significantly higher than that in non-A blood groups (OR = 1.42; 95% CI 1.05-1.93) 5.
- Genetic factors may also play a role in the development of precancerous gastric lesions, with blood type A being a potential risk factor 2.
Clinical Implications
- The ABO blood group may be a useful marker for identifying individuals at increased risk of gastric cancer 6.
- Patients with blood type A may require closer monitoring and screening for gastric cancer 6.
- The O blood group may be a prognostic factor for gastric cancer patients, with individuals having type O blood showing a better 5-year survival rate (hazard ratio = 0.97,95% confidence interval = 1.67-3.92) 6.