Prognostic factors for satellitosis or in-transit metastasis in cutaneous squamous cell carcinoma: A multicentric cohort study

Background: Satellitosis or in-transit metastasis (S-ITM) has clinical outcomes comparable to node-positivity in cutaneous squamous cell carcinoma (cSCC). There is a need to stratify the risk groups.Objective: To determine which prognostic factors of S-ITM confer an increased risk of relapse and cSCC-specificedeath.Methods: A retrospective, multicenter cohort study. Patients with cSCC developing S-ITM were included. Multivariate competing risk analysis evaluated which factors were associated with relapse and specific death.Results: Of a total of 111 patients with cSCC and S-ITM, 86 patients were included for analysis. An S-ITM size of $20 mm, >5 S-ITM lesions, and a primary tumor deep invasion was associated with an increased cumulative incidence of relapse (subhazard ratio [SHR]: 2.89 [95% CI, 1.44-5.83; P = .003], 2.32 [95% CI, 1.13-4.77; P = .021], and 2.863 [95% CI, 1.25-6.55; P = .013]), respectively. Several >5 S-ITM lesions were also associated with an increased probability of specific death (SHR: 3.48 [95% CI, 1.18-10.2; P = .023]).Limitations: Retrospective study and heterogeneity of treatments.Conclusion: The size and the number of S-ITM lesions confer an increased risk of relapse and the number of S-ITM an increased risk of specific-death in patients with cSCC presenting with S-ITM. These results provide new prognostic information and can be considered in the staging guidelines. ( J Am Acad Dermatol 2023;89:119-27.)