Surveillance Imaging in Cutaneous Squamous Cell Carcinoma: A Retrospective Analysis Informing Surveillance Recommendations

Background: Imaging surveillance for high-stage (HS), regionally metastatic (RM), and unresectable (UR) cutaneous squamous cell carcinoma (CSCC) is not standardized, and evidence guiding post-treatment imaging is limited. Objective: To characterize imaging surveillance practices for HS, RM, and UR CSCC at a single high-volume cancer center and propose tailored surveillance protocols. Methods: Retrospective cohort study of patients with HS, RM, or UR CSCC discussed at a multidisciplinary tumor board (January 2021-November 2024). Results: For HS CSCC, CT of the regional nodal basin was most common (83.9%), typically every 6 months for 2 years (61.3%). RM CSCC most frequently underwent CT (64.7%) or PET/CT (35.3%), most commonly every 6 months for 3 years (67.6%). UR CSCC surveillance included CT (57.9%) and PET/CT (42.1%), most often every 3 months for year 1 and every 6 months for years 2–3 (52.6%). Conclusions and Relevance: Imaging surveillance practices for advanced CSCC varied by disease extent and treatment. Proposed surveillance recommendations include CT every 6 months for 2 years (HS), CT every 6 months for 3 years (RM), and CT or PET/CT every 3 months for year 1 then every 6 months in years 2–3 (UR). These findings reflect real-world practice and may inform development of structured surveillance protocols.