Associations between ABO blood groups and biochemical recurrence after radical prostatectomy.

Background: Recent studies have demonstrated associations between ABO blood groups and prognosis in various types of cancers. The aim of this study was to investigate the association between ABO blood groups and biochemical recurrence (BCR) after radical prostatectomy (RP). Methods: A total of 555 patients with prostate cancer who underwent RP were included in the study. No patients received neoadjuvant and/or adjuvant therapy. The effect of ABO blood groups on BCR was examined using univariate and multivariate analyses. Results: During the follow-up period (mean, 52.0 months), 166 patients (29.9%) experienced BCR, with a 5-year BCR-free rate of 67.3%. Although the ABO blood group was not a significantly associated with BCR in the univariate analysis, it was an independent predictor of BCR in the multivariate analysis: blood type O patients had a significantly lower risk of BCR compared to type A patients (Hazard ratio, 0.608; 95% confidence interval, 0.410-0.902; P = 0.014). Further analyses revealed that surgical margin status confounded the assessment of the association between the ABO blood group and BCR. In the analyses of patients with a negative surgical margin, the 5-year BCR-free rate in blood type O patients was a significantly higher than that in type A patients (91.2% vs. 71.0%; P = 0.026). Conclusion: Blood type O is significantly associated with a decreased risk of biochemical recurrence after radical prostatectomy. Further studies are needed to clarify the nature of this association.