Epidemiology of sinonasal undifferentiated carcinoma in Queensland, Australia, 1982-2024: insights from a population-based cohort

Background Sinonasal undifferentiated carcinoma (SNUC) is a rare and aggressive group of malignant tumours arising from the nasal cavity and paranasal sinuses. We present here the details of a population-based cohort over four decades. Materials and methods A retrospective cohort study was conducted using all histologically confirmed cases of SNUC diagnosed in Queensland between 1982 and 2024. Demographics, clinical features, treatment history and outcomes were extracted from the Queensland Oncology Repository. The Kaplan–Meier method was used to calculate 5-year all-cause survival by key variables of interest. Results Sixty-four cases were included in the study. Median age at diagnosis was 56.5 years. There was some evidence of an increase in the proportion of females, from 27% to 50% over the study period ( P = 0.08). Over half (59%) were stage IV at diagnosis. The age-standardised incidence was 0.05 per 100 000 population and remained stable over time. Dual modality treatment was the most common approach ( n = 29, 45%), with 79% of surgery, 53% of radiotherapy and 54% of chemotherapy requiring patients to travel elsewhere for treatment. Five-year all-cause survival was 35% [95% confidence interval (CI) 24% to 48%] for the total study cohort but varied by treatment modality (70%, 95% CI 33% to 89% for trimodal therapy, P = 0.04) and smoking status (76%, 95% CI 48% to 90% for never smokers, P = 0.01). Conclusions Our study offers real-world insights into the epidemiology of this very rare malignancy in one of the larger cohorts published to date. Development of a specialised national registry in Australia would enhance efforts to better understand and treat SNUC.