Risk of second primary malignancy after nasopharyngeal carcinoma in the United States: A population-based study

Background. The purpose of this study was to evaluate the incidence of second primary malignancies in patients diagnosed with an index nasopharyngeal carcinoma (NPC) in the United States. Methods. The cohort was assembled from the Surveillance, Epidemiology, and End Results (SEER) database with a primary NPC between 1973 and 2005. Results. There was a 47% increased risk of second primary malignancy. The sites with increased risk include the oral cavity and pharynx (standardized incidence ratio [SIR] 57.11; 95% confidence interval [CI] =5.21-9.49), esophagus (SIR=3.50; 95% CI=1.68-6.44), nose, nasal cavity, and middle ear (SIR=15.54; 95% CI=5.70-33.83), and lung and bronchus (SIR=2.39; 95% CI=1.91-2.96). Conclusion. Patients with NPC are likely at a significant risk for second primary malignancies, most notably in the oral cavity and pharynx, which is most likely related to genetic susceptibility, increased surveillance, and treatment effects. (c) 2015 Wiley Periodicals, Inc.