Survival Outcomes in Sinonasal Poorly Differentiated Squamous Cell Carcinoma.

Objective: Sinonasal squamous cell carcinoma (SCC) is rare with no consensus on treatment regimen. Our goal is to analyze treatment outcomes in poorly differentiated SCC (PDSCC) using a large national database.

Study Design: Retrospective database study.

Methods: The National Cancer Database was queried for sinonasal invasive SCC, grade 3 (poorly differentiated) from 2004 to 2014. Patient demographics and tumor and treatment characteristics were tabulated. Kaplan-Meier (KM) analysis was performed to compare overall survival (OS) between histology subtype and primary site. Multivariable Cox proportional hazards regression was performed for statistical analysis of treatment regimen on OS.

Results: A total of 1,074 patients were identified. The maxillary sinus was the most common site (45%). T4 tumors were observed in 50% of patients, with most patients treated at high-volume facilities (77%). In KM analysis, spindle cell SCC histological subtype, primary tumors of the maxillary sinus, and poorly differentiated grade had worse OS. In our Cox-PH model, higher T stage and age were associated with worse OS. Those treated at a high-volume facility and those who underwent surgical resection followed by adjuvant radiation had improved OS. Chemotherapy within the treatment regimen did not confer survival benefit except in surgical patients when positive margins were present, and surgery with adjuvant chemoradiation trended toward improved survival.

Conclusions: Sinonasal PDSCC appears to be best treated at high-volume centers with surgical resection followed by adjuvant radiation. Poorly differentiated grade has worse OS compared to more differentiated tumors. Chemotherapy along with adjuvant radiation may have a role in patients with positive surgical margins.

Level Of Evidence: 4 Laryngoscope, 131:E1040-E1048, 2021.