Background: With emerging new systemic treatments for metastatic melanoma, early detection of disease recurrence is increasingly important. We investigated risk of melanoma recurrence in patients diagnosed with a localised melanoma at high-risk of spread.
Patients and methods: In a cohort of patients with localised tumour stage T1b to T4b melanoma, recruited prospectively between 2010 and 2014 in Queensland, Australia, we compared disease-free survival (DFS) by tumor stage defined by the 7th versus 8th American Joint Committee on Cancer (AJCC) melanoma staging guidelines, and used Cox regression to examine associations between patient and tumor factors and melanoma recurrence.
Results: Amongst 700 patients with high-risk primary melanoma (mean age 62, 59% male), independent predictors of recurrence were head or neck site of primary, ulceration, thickness and mitotic rate >3/mm2. 94 (13%) patients developed a recurrence within 2 years of diagnosis: 66 (70%) locoregional, and 28 (30%) at distant sites. After surgery for locoregional disease, 37 (58%) remained disease-free at 2 years, 7 (11%) developed new locoregional recurrence and 20 (31%), distant disease. 2-year DFS ranged from 95% for T1b melanomas to 67% for T4b and was similar when comparing 7th and 8th AJCC edition. Patients with T2a to T4a tumors who did not have a sentinel lymph node biopsy (SLNB) at diagnosis had significantly lower DFS than patients with same tumor stage and a negative SLNB.
Conclusion: We estimate that almost 15% of patients diagnosed with a high-risk primary melanoma will experience disease recurrence within 2 years. SLNB positivity, head or neck location of initial tumor and signs of rapid tumor growth are associated with primary melanoma recurrence.