Prognostic value of ABO blood group in southern Chinese patients with established nasopharyngeal carcinoma

Background: ABO blood group is associated with aetiology of nasopharyngeal carcinoma (NPC); however, the effect of it on survival of patients diagnosed with NPC has not been explored. Methods: We retrospectively analysed two cohorts of southern Chinese patients with WHO histological type III: intensity-modulated radiotherapy (IMRT) cohort, 924 patients; and conventional radiotherapy (CRT) cohort, 1193 patients. Associations of ABO blood group with survival were estimated using Cox regression. Results: In IMRT cohort, we observed significant associations of blood type A with overall survival (OS) and distant metastasis-free survival (DMFS), compared with type O, after adjusting for prognostic factors. Compared with non-A blood types (B, AB, and O), type A patients had significantly lower OS and DMFS (adjusted hazard ratio (HR) = 1.49, 95% CI 1.03-2.17, P = 0.036; HR = 1.68, 95% CI 1.13-2.51, P = 0.011, respectively); similar results were obtained in CRT cohort. Subgroup analyses of the entire population showed that lower OS conferred by blood type A was not significantly modified by age, smoking status, drinking status, immunoglobulin A against Epstein-Barr virus viral capsid antigen (VCA-IgA) titre, or chemotherapy; however, lower OS was not observed in female patients or patients with early clinical stage disease. Conclusion: ABO blood group is associated with survival in NPC; patients with blood type A had significantly lower OS and DMFS than patients with non-A blood types.