Risk of second primary malignancy in patients with sinonasal tumors: a population‐based cohort study.

Background: The 5‐year overall survival rate for patients with sinonasal cancers has remained around 50% for the last 3 decades. Prior studies on head and neck cancers have suggested that 1 reason for poor survival is the frequent development of second primary malignancies (SPMs). The purpose of this study is to assess overall and site‐specific risks of SPM following treatment of sinonasal malignancy. Methods: A retrospective, population‐based cohort study was performed on 2614 patients in the Surveillance, Epidemiology, and End Results (SEER) database who were diagnosed with primary sinonasal malignancy between 1973 and 2014. Standardized incidence ratios (SIRs) and absolute excess risks (AERs) were calculated to assess risk of SPM relative to incidence in the general population. Results: A total of 422 (16.1%) patients with primary sinonasal malignancies developed a total of 480 SPMs. This cohort had a significantly higher frequency of SPMs than expected in the general population (SIR 1.32; 95% confidence interval [CI], 1.20 to 1.44; AER 53.41). Site‐specific analyses of SIRs suggested highest risk of malignancy in the sinonasal tract (SIR 75.64; 95% CI, 53.53 to 103.83; AER 17.22), followed by bone, eye and orbit, oral cavity and pharynx, and lung and mediastinum. Conclusion: Patients with history of sinonasal cancer are at significantly increased risk of developing an SPM. Careful monitoring for development of additional tumors may be warranted. [ABSTRACT FROM AUTHOR]