O Blood Type Is Associated with Unfavorable Distant-metastasis-free Survival in Female Patients with Nasopharyngeal Carcinoma: A Retrospective Study of 2439 Patients from Epidemic Area.

: To identify the association between ABO blood type and the survivals in nasopharyngeal carcinoma patients. : We retrospectively analyzed 2439 consecutive non-metastasis nasopharyngeal carcinoma patients between January 2001 and December 2004 at the Sun Yat-sen University Cancer Center. Survival outcomes were compared using Kaplan-Meier method. Univariate and multivariate analysis was performed by Cox regression model. Chi-square test was performed to compare categorical variables. : In the whole patients, compared with non-O blood type (A, B, and AB) patients, O blood type patients had significantly lower 5-year distant metastasis-free survival (DMFS) (adjusted hazard ratio (aHR)= 1.268, 95% CI 1.010-1.592, P=0.041). Moreover, we observed in female patients, O blood type patients had significantly lower 5-year overall survival (OS), disease-specific survival (DSS) and DMFS than those with non-O blood type (aHR=1.495, 95% CI 1.032-2.165, P=0.034 for OS; aHR=1.566, 95% CI 1.054-2.328, P=0.026 for DSS; aHR=1.779, 95% CI 1.056-2.998, P=0.030 for DMFS). In male patients, there was no significant difference observed between O blood type patients and non-O blood type patients in any survival endpoints. : O blood type was associated with an unfavorable DMFS in female patients with nasopharyngeal carcinoma in epidemic area, which might contribute to unfavorable OS and DSS in female patients, even contribute to a lower DMFS in the whole patients. It might be beneficial to predict metastasis so as to guide the treatment in female patients with nasopharyngeal carcinoma in epidemic area.