International, Multi-Institutional Evaluation of Practice Patterns and Outcomes for Recurrent and Metastatic Sinonasal Undifferentiated Carcinoma.

Objectives: The aims of this study were to analyze the clinical characteristics of patients with recurrent and metastatic sinonasal undifferentiated carcinoma (SNUC) and evaluate the current treatment strategies to help guide future management.

Design: This is a retrospective cohort study.

Setting: The study was conducted at six international tertiary treatment centers.

Participants: Patients with documented diagnoses of recurrent or metastatic SNUC since 1983 were included in the study.

Main Outcome Measures: Patient demographics and clinical characteristics were collected. Primary outcome measures included disease-specific survival (DSS), overall survival (OS), and time to recurrence (TTR) following initial treatment. Further univariable and multivariable analyses were performed to assess for prognostic factors.

Results: A total of 97 patients with a mean (standard deviation [SD]) age of 52.4 (15.6) were identified, 15 of whom presented with metastatic SNUC and 90 of whom developed recurrence. Management in both populations was widely variable. For patients with metastatic disease, the 1-year DSS probability was 33.3% (95% confidence interval [CI], 10.8-100%). For patients with recurrent SNUC, the 1- and 5-year DSS probabilities were 45.7% (95% CI, 31.9-65.6%) and 8.6% (95% CI, 2.9-25.3%), respectively. The median (interquartile range [IQR]) TTR was 8 months (3-18.5 months). Multivariable analyses revealed a significant association between orbital involvement on initial presentation and TTR (hazard ratio [HR] = 3.28; 95% CI, 1.45-7.42;  = 0.004).

Conclusions: To our knowledge, this is the first study addressing metastatic and recurrent SNUC based on a large patient cohort. Orbital extension of the primary SNUC may predict a higher probability of recurrence following treatment, suggesting the possible utility of a more aggressive treatment in this subgroup of patients. A heterogenous patient population and wide variability in management emphasize the challenges in standardizing care; however, dismal survival rates demonstrate the necessity for further evaluation of current approaches to improve evidence-based recommendations.