Identifying High-Risk Features and Improving Follow-Up Strategies in Thin Melanoma: A Retrospective Cohort Study

Background Thin melanomas (TMs) are typically associated with favorable outcomes, but a subset of patients experiences recurrence and worse survival. Prognostic factors for recurrence in TM remain inadequately characterized. Objective This study aims to identify clinical and histopathological factors associated with recurrence and explore implications for follow-up strategies in TM. Methods A retrospective cohort study included 308 patients with TM (Breslow thickness 0.1–1 mm) treated at two medical institutions between 1998 and 2017. Patients were stratified into recurrence (R, n=53) and non-recurrence (NR, n=255) groups. Clinical and histopathological variables were analyzed, and survival outcomes were assessed. Results Recurrence was associated with nodular histology (13.21% vs. 3.14% in NR, p=0.016), presence of ulceration (16.98% vs. 2.75%, p<0.001), and higher mitotic rate (2.1 vs. 0.6 mitoses/mm², p<0.001). Ultra-thin melanoma (Breslow ≤ 0.5 mm) was protective against recurrence (HR=0.08, p<0.001). Recurrence reduced 10-year overall survival (62.26% vs. 95.69%, p<0.001) and melanoma-specific survival (64.15% vs. 100%, p<0.001). Conclusions Prognostic factors like ulceration, mitotic rate, and histological subtype should guide individualized follow-up strategies. Ultra-thin melanomas may require less intensive monitoring, while melanomas >0.5 mm could benefit from extended follow-up beyond current guidelines. Tailoring surveillance based on recurrence risk could improve outcomes and quality of care for TM patients.