Patterns and prognostic factors of metastasis in Latino/Hispanic patients with melanoma and negative lymph nodes.

Introduction: Malignant melanoma presents with diverse clinical and histological manifestations that vary per population. Lymph node status, assessed through sentinel lymph node biopsy, is a widely accepted standard of care and a key prognostic indicator. This study aims to identify clinical outcomes, clinicopathologic factors, recurrence patterns, metastatic spread patterns and risk factors associated with lymph node-negative melanoma in our Latino/Hispanic patient population.

Methods: We included patients diagnosed with lymph node-negative melanoma at the Instituto Nacional de Enfermedades Neoplásicas, Lima, Peru, from 2010 to 2019. Cox regression analysis was used to assess prognostic factors.

Results: The study included 249 patients with lymph node-negative melanoma, with a median follow-up time of 25 months. Recurrence was observed in 27% of patients, with a mean age of 65 years compared to 60 years in the non-recurrent group. With a median follow-up of 35 months, the 3-year recurrence-free survival (RFS) rates and overall survival (OS) were 75% and 94%, respectively. The 3-year OS rate was 97% and 88% for non-recurrent and recurrent patients, respectively (p = 0.002). The predictors of RFS were Breslow index (hazard ratio (HR) = 1.098, 95%CI: 1.051-1.146, p < 0.001) and number of mitoses per mm² (HR = 2.105, 95%CI: 1.150-3.852, p = 0.016). Age was the only predictor for lymph node recurrence (HR = 1.053, 95%CI: 1.010-1.098, p = 0.016), and Breslow index for distant metastasis (HR = 1.126, 95%CI:1.059-1.196, p < 0.001). Breslow index was the only prognostic factor for OS (HR = 1.090, 95%CI:1.034-1.150, p = 0.001).

Conclusion: The Latino/Hispanic population has unique characteristics and prognostic factors for oncologic outcomes. Increased Breslow depth and number of mitoses per mm² were significant predictors of recurrence in lymph node-negative melanoma. There is a need for personalised risk assessment and management strategies in this population in terms of surveillance and adjuvant therapies. Further molecular and genetic predictors and markers of recurrence need to be investigated.