Effect of Blood Type on Mortality Among Patients with Brain Metastases

Objective ABO blood type has been associated with mortality among patients with cancer, but this association has thus far not been investigated among patients with brain metastases. Hence, we aimed to investigate the association between ABO blood type and mortality among patients who underwent surgical resection of brain metastases. Methods A single-center retrospective study of patients who underwent surgical resection of brain metastases between 2011 and 2019 was conducted. Cox proportional hazards models were constructed, adjusting for potential confounders, to evaluate whether blood type was independently associated with overall mortality. Results A total of 158 patients were included in the analysis. The mean (SD) age of the cohort was 59.3 (12.0) years, and 67.7% of patients were female. The median overall survival of patients with AB was 11.2 months, while the median overall survival of patients with blood types O, B, and A were 11.7, 13.5, and 14.4 months respectively. On multivariate analysis adjusting for potential confounders, there was a statistically significant association between blood type AB and a higher risk of overall mortality (HR=2.42, 95% CI=1.20, 4.86, p=0.013). Conclusions Blood type AB was independently associated with a higher risk of overall mortality among patients who underwent surgical resection of brain metastases. We hypothesize that antibodies against blood type antigens A and/or B have anti-tumor activity in patients with brain metastases. Further studies are needed to validate our conclusions and hypothesis.