Impact of extranodal extension in metastatic cutaneous squamous cell carcinoma of the head and neck: a systematic review and meta‐analysis

Objective: The aim of this study is to analyze the impact of extranodal extension (ENE) on survival outcomes for patients with metastatic cutaneous head and neck squamous cell carcinoma (cHNSCC). Methods: The pooled hazard ratios (HRs) and the 95% confidence interval (CI) were calculated to define the impact of ENE on overall survival (OS) and disease-free survival (DFS). Results: A total of 2076 patients (males: 84.4%) with a median age of 73.3 years were included. The incidence of ENE was 65.6% (N = 1299/1979). The median follow-up time was 38.4 months (95% CI: 21–38.4). The estimated pooled HRs were 1.31 (95% CI: 0.72–2.39; p = 0.28) and 1.80 (95% CI: 0.53–6.10; p = 0.22) for OS and DFS, respectively. Conclusions: ENE may not be a reliable prognostic factor in metastatic cHNSCC. Further prospective studies are needed to refine risk stratification and improve the current nodal classification system.