The relation between ABO blood groups and clinicopathologic characteristics of the patients with gastric adenocarcinomas.

Objectives: This study aimed to examine the association between blood groups and clinicopathological factors that could affect the prognosis of patients with gastric cancer. Material and Methods: In this retrospective single-center study, patients with gastric adenocarcinoma were obtained from a prospectively maintained database. The association between blood groups and clinicopathologic characteristics including sex, age, tumor location, tumor size, tumor stage, metastatic lymph node ratio (MLR), lymphovascular invasion, and perineural invasion were analyzed. Results: The study included 91 female and 221 male patients. The blood group distribution was A>O>B>AB both in the patients and healthy donors. Non-O blood types were more common in cancer patients than in healthy donors (p= 0.038). However, there was no significant association between sex, age, tumor location, tumor stage, lymph node status, lymphovascular invasion, and perineural involvement and blood groups. ≥7 lymph node involvement and MLR of >0.6 were significantly more common in patients with blood group A than in those with non-A blood groups (p= 0.034 and p= 0.018; respectively). Conclusion: The findings of this study suggest that blood group A patients are associated with higher MLR and N3 involvement, so it is possible that these patients with gastric cancer have a poorer prognosis.