Prognostic relevance of ABO blood group system in non-metastatic renal cell carcinoma: An analysis of two independent European cohorts with long-term follow-up.

Background: The ABO blood group system has been previously discussed as a risk factor to develop, as well as a prognostic factor in non-metastatic renal cell carcinoma (RCC). Controversial findings have been reported in different populations of RCC patients with rather short follow-up periods. In this study, we aimed to clarify the distribution and prognostic role of ABO blood groups upon 15 years of median follow-up in non-metastatic RCC patients.