Determinants of Patient Refusal of Postoperative Radiation Therapy in Sinonasal Squamous Cell Carcinoma.

 Although adjuvant radiotherapy may be indicated in patients with sinonasal squamous cell carcinoma (SNSCC) following primary surgery, some patients choose to forgo recommended postoperative radiation therapy (PORT). This study aimed to elucidate factors associated with patient refusal of recommended PORT in SNSCC and examine overall survival.  Retrospective analysis of patients with SNSCC treated with primary surgery from the National Cancer Database diagnosed between 2004 and 2016. A multivariable logistic regression model was created to determine the association between clinical or demographic covariates and likelihood of PORT refusal. Unadjusted Kaplan-Meier estimates, log-rank tests, and a multivariable Cox proportional hazard model were used to assess overall survival.  A total of 2,231 patients were included in the final analysis, of which 1,456 (65.3%) were males and 73 (3.3%) refused recommended PORT. Patients older than 74 years old were more likely to refuse PORT than those younger than 54 (odds ratio [OR] 3.43, 95% confidence interval [CI]: 1.84-6.62). Median survival among the entire cohort, those who received recommended PORT, and those who refused PORT was 83.0 months (95% CI: 74.6-97.1), 83.0 months (95% CI: 74.9-98.2), and 63.6 months (95% CI: 37.3-101.4), respectively. Refusal of PORT was not associated with overall survival (hazard ratio: 0.99, 95% CI: 0.69-1.42).  PORT refusal in patients with SNSCC is rare and was found to be associated with several patient factors. The decision to forgo PORT is not independently associated with overall survival in this cohort. Further study is required to determine the clinical implications of these findings as the treatment decisions are complex.