47 | RECURRENCE DEFINES PROGNOSIS IN THICK MELANOMA: A LONG-TERM SINGLE-CENTER EXPERIENCE

S. Apa¹, P. Del Fiore², C. Trevisiol², G. Madeo³, N. Romagnolo⁴, F. Cassalia², A. Acciardi², S. Mocellin^2|3, M. Alaibac⁴ | ¹Department of Medicine (DIMED), School of Medicine, University of Padova, Italy; ²Soft-Tissue, Peritoneum and Melanoma Surgical Oncology Unit, Veneto Institute of Oncology IOV - IRCCS, Italy; ³Department of Surgery, Oncology and Gastroenterology (DISCOG), University of Padova, Italy; ⁴Dermatology Unit, Department of Medicine, University of Padova, Italy

Introduction. Thick cutaneous melanoma remains a high-risk malignancy despite advances in diagnosis and treatment. Although Breslow thickness is a well-established prognostic factor, outcomes among patients with thick melanoma remain heterogeneous. The aim of this study was to evaluate long-term outcomes, recurrence patterns, and prognostic factors in a cohort of patients with thick cutaneous melanoma.
Materials and Methods. We retrospectively analyzed 278 consecutive patients diagnosed with thick cutaneous melanoma (Breslow thickness >4 mm) between 2000 and 2020 at a tertiary referral center. Clinicopathological variables included age, sex, Breslow thickness, mitotic rate, ulceration, primary tumor site, and sentinel lymph node biopsy (SLNB) status. Overall survival (OS) and melanoma-specific survival (MSS) were estimated using Kaplan–Meier analysis and evaluated through Cox proportional hazards models.
Results. After a median follow-up of 95 months, 138 patients (49.6%) developed disease recurrence. The most frequent first recurrence pattern was in-transit or regional cutaneous recurrence (33.3%), followed by distant metastasis (27.5%) and regional nodal recurrence (25.4%). During follow-up, 122 melanoma-specific deaths and 188 deaths from any cause were recorded. Patients who experienced recurrence showed markedly worse outcomes compared with those who remained recurrence-free. Five-year MSS was 49.4% in patients with recurrence and 78.6% in those without recurrence, while five-year OS was 44.2% and 65.0%, respectively. In multivariable analysis, Breslow thickness, ulceration, and SLNB status emerged as independent prognostic factors for both melanoma-specific and overall survival.
Conclusions. Despite advances in melanoma management, thick melanoma remains associated with a considerable risk of recurrence and melanoma-related death. In our cohort, recurrence identified a subgroup of patients with substantially worse long-term outcomes. Traditional clinicopathological factors, including Breslow thickness, ulceration, and sentinel lymph node status, retained important prognostic value. These findings underline the complexity of thick melanoma and support ongoing efforts to better identify patients at greatest risk.