Sinonasal Undifferentiated Carcinoma: An Update on Survival and Prognostic Markers

Sinonasal undifferentiated carcinoma (SNUC) is a rare tumor most often arising from the sinonasal cavity and presenting at a late stage with poor overall survival. There are no agreed upon guidelines for treatment and there are few studies showing survival benefits for any treatment modality. We have previously presented data from 19 patients from 1995 to 2008. Here, we present follow-up data from our institution for 21 additional patients (total of 40) treated between 1995 and 2017. The aims of this study were to compare survival outcomes based on treatment modality and to assess for clinical factors associated with poor patient outcomes (defined as survival < 3 years).

Methods We performed a single-institution retrospective case series of patients with SNUC diagnosed or treated at our institution between 1995 and 2017 (n = 40). Clinical, pathologic, and survival data were collected. Patients were stratified by treatment type and by survival expectation where appropriate. Kaplan–Meier and chi-square statistics were used for analysis.

Results The median age at diagnosis was 58 years (range of 19–83 years). Median follow-up time was 21 months (range of 1–145 months). One patient (2.5%) was treated with surgery alone; 16 patients (40%) with surgery in addition to adjuvant radiation, chemotherapy, or both (CRT); and 20 patients (50%) with CRT alone. Twenty-three patients (62.2%) had persistent or recurrent disease after treatment. Of these, 68% were locoregional recurrence or persistence while 32% were distant failures. Overall survival was 66.7% at 1 year and 44.7% at 5 years. Disease-free survival was 45.7% at 1 year and 40.0% at 5 years. There was no difference in overall survival (p = 0.55), recurrence (p = 0.62), or distant metastases (p = 0.74) between patients treated with surgery with or without CRT and patients treated with CRT alone. Of the 20 SNUC-related deaths, 18 (90%) occurred within the first 3 years of treatment. We compared these patients with patients who survived past 3 years to assess for clinical or treatment factors associated with poor survival. Patient age (p = 0.27), sex (p = 0.95), BMI (p = 0.42), tumor stage (p = 0.17), nodal involvement (p = 0.17), and treatment modality (0.65) were not found to be significant. Smoking status (current or former smoker) was the only factor found to be significantly associated with death within 3 years (p = 0.05).

Conclusion Overall and disease-free survival rates remain poor and there continues to be no clear survival benefit from surgery with adjuvant CRT compared with upfront CRT. There is a subset of patients who do poorly with the majority dying from disease within 3 years. Smoking status was the only clinical, staging, or treatment factor found to be significantly associated with poor prognosis. These patients may warrant further investigation with next-generation sequencing to determine possible genetic factors contributing to poor survival.