Survival outcomes in head and neck squamous cell carcinoma of unknown primary: A national cohort study

Introduction To investigate factors influencing survival in head and neck squamous cell carcinoma of unknown primary (HNSCCUP). Methods A retrospective observational cohort study was conducted, over 5 years from January 2015, in UK Head and Neck centres, of consecutive adults undergoing 18F‐Fluorodeoxyglucose‐PET‐CT within 3 months of diagnosis with metastatic cervical squamous cell carcinoma. Patients treated as HNSCCUP underwent survival analysis, stratified by neck dissection and/or radiotherapy to the ipsilateral neck, and by HPV status. Results Data were received from 57 centres for 965 patients, of whom 482 started treatment for HNSCCUP (65.7% HPV‐positive, n = 282/429). Five‐year overall survival (OS) for HPV‐positive patients was 85.0% (95% CI 78.4–92.3) and 43.5% (95% CI 32.9–57.5) for HPV‐negative. HPV‐negative status was associated with worse OS, disease‐free (DFS), and disease‐specific (DSS) survival (all p