Introduction: Cutaneous Squamous Cell Carcinoma (cSCC) is one of the most prevalent skin cancers worldwide, with the highest incidence observed in Australia and New Zealand. Nodal metastasis is found in 5% of patients with cSCC and extracapsular spread is recorded in between 70-85% of the nodal metastasis. In oral SCC, ECS is associated with worse survival outcomes. This study aims to assess the prognostic significance of ECS in cSCC. Methods: A retrospective review was conducted from a prospectively maintained head and neck cancer database at The Sydney Head and Neck Cancer Institute and included all patients with head and neck cSCC metastasised to the parotid or neck, treated with curative surgical resection between 2000 and 2022. Patients with incomplete ECS data were excluded. Cox regression and Kaplan-Meier methods were used to assess associations with disease-specific survival (DSS) and Disease-Free Survival (DFS). Results: A total of 555 patients were included. The cohort was primarily male (85.4%) with a mean age of 74.9 (SD = 10.8) years and 460 patients (83%) with documented ECS. Of those, 54 (11.7%) had ECS ≤5mm, 5 (1.1%) had ECS between 5mm and 10mm, and 401 patients (87.2%), had ECS >10mm. Kaplan-Meier analysis, Cox univariable, and multivariable analyses showed that ECS has no impact on DSS (HR = 0.99, 95% CI 0.41 - 2.42, p = 0.99 for UVA; HR = 1.01, 95% CI 0.22 – 4.71, p = 0.986 for MVA). Patients with ECS >10mm were found to have worse DFS on univariable analysis (HR = 1.54, 95% CI 1.14 – 2.07, p 0.005); however, when adjusted for size, number of deposits, and age on multivariate Cox regression analysis, this was not found to be a significant prognostic determinant for DFS (HR = 1.365, 95% CI 0.86 – 2.16, p = 0.185 for MVA). Conclusion: This study found that ECS is not a prognostic factor for DSS and DFS amongst patients with cSCC.