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. Materials and methods: We evaluated the distribution and prognostic significance of ABO blood group system in two independent cohorts (n = 405 and n = 1473) of non-metastatic RCC patients, who underwent curative (partial or total) nephrectomy between 1998 and 2012 at two tertiary academic centers. Cancer-specific survival, metastasis-free survival, as well as overall survival (OS) were assessed using the Kaplan-Meier method, univariable- and multivariable Cox regression models were applied, respectively. Results: In the two cohorts, blood groups were not associated with any clinical endpoints (for cohort 2: Cancer-specific survival (HR = 1.233; 95%CI 0.998-1.523, P = 0.052), metastasis-free survival (HR = 1.161; 95%CI 0.952-1.416, P = 0.142) and OS (HR = 1.037; 95%CI 0.890-1.208, P = 0.641), respectively). Compared to 250.298 healthy blood-donors of the Styrian state, the distribution of blood groups was (624 (42.4%) versus 106.861 (42.7%) in group A, 191 (13%) vs. 34.164 (13.7%) in group B, 575 (39%) versus 93.579 (37.4%) in group O and 83 (5.6%) vs. 15.694 (6.3%), P = 0.467). Conclusion: In this large study with the longest period of follow-up reported to date, the ABO blood group system could not be validated as a prognostic factor in predicting important clinical endpoints in non-metastatic RCC patients. (C) 2021 The Author(s). Published by Elsevier Inc.