Epidemiology and treatment outcomes of cutaneous squamous cell carcinoma extending to the temporal bone

BACKGROUND: Accurate epidemiological and outcomes data regarding cutaneous squamous cell carcinoma (cSCC) extending to the temporal bone is lacking. METHODS: Retrospective analysis of 167 Australian patients with primary and peri‐temporal bone cSCC. RESULTS: cSCC extending from secondary subsites (93.4%) was 14 times more frequent than primary temporal bone SCC (6.6%). For patients who underwent curative surgery ± post‐operative radiotherapy (n = 146, 87.4%), 5‐year disease‐free survival, locoregional recurrence‐free survival, disease‐specific survival, and overall survival was 53.0%, 59.4%, 67.9%, and 44.7%, respectively. External ear and pre‐auricular tumors, salvage surgery, tumor size (≥40 mm medial‐lateral), nodal disease, and involved margins were negative predictors of survival in multivariable analysis. CONCLUSION: In regions of high sun exposure, cSCCs extending to the temporal bone are more common than primary cancers. Outcomes are improved with clear margins, justifying the need for radical resection. Further research regarding pre‐auricular cancers is required given poorer associated survival outcomes.