Epidemiology of nasopharyngeal carcinoma in the United States: improved survival of Chinese patients within the keratinizing squamous cell carcinoma histology.

ABSTRACT

BACKGROUND: This study examined potential survival differences among nasopharyngeal carcinoma (NPC) patients from various ethnicities in the United States. PATIENTS AND METHODS: A total of 2436 newly diagnosed NPC patients from 1992 to 2002 were analyzed from the population-based Surveillance, Epidemiology, and End Results (SEER) program. Five-year survival rate estimates and Kaplan-Meier survival curves were calculated. Cox proportional hazard ratios (HRs) were used to identify independent prognostic factors for survival. RESULTS: By multivariate analyses, early age of diagnosis, localized stage at presentation (versus distant, HR=0.35; P<0.0001), radiation therapy (versus none; HR=0.48; P<0.0001), undifferentiated non-keratinizing carcinoma (versus keratinizing squamous cell carcinoma; HR=0.67; P<0.0001), and Chinese ethnicity (versus Caucasian; HR=0.78; P=0.0010) were associated with improved survival. Within keratinizing squamous cell carcinoma histology, the survival advantage of Chinese patients remained even after adjustment for other prognostic factors. CONCLUSIONS: The significant survival advantage of Chinese NPC patients within the keratinizing squamous cell carcinoma histology contributed largely to Chinese ethnicity being an independent and favorable prognostic factor for survival in NPC.