[Translated article] Longitudinal Study of Different Progression Patterns in High-Risk Cutaneous Squamous Cell Carcinoma

Background and objective: Cutaneous squamous cell carcinoma (cSCC) is the second leading cause of skin cancer mortality in Europe. Few studies have analyzed the different pathways of this tumor progression in its natural history. The main objective of this study was to analyze the different metastatic and progression pathways and their temporal occurrence in the evolution of cSCC. Material and method: We conducted a multicenter, retrospective, and observational study of consecutive high -risk sSCCs included in the SQUAMATA project. Results: A total of 222 out of the 1346 patients included relapsed. The most frequent route of progression was the lymphatic one (62.6%). A total of 20.2% of the cases with lymphatic progression developed distant metastases. Only 1 case (3.1%) of distant metastasis followed local recurrence without previous lymphatic metastasis. The median time to disease -related mortality was longer in patients who developed systemic metastases than in those who died of locoregional progression.