Value of sentinel lymph node biopsy and adjuvant interferon treatment in thick (>4 mm) cutaneous melanoma: an observational study.

Background: The role of sentinel lymph node biopsy and the benefit of immunotherapy with interferon in thick (>4 mm) melanomas remain uncertain.

Objectives: Our aim was to assess the value of both sentinel lymph node (SLN) biopsy and immunotherapy in the prognosis of thick melanomas.

Methods: A retrospective study based on a computerized patient database in which patients have been prospectively collected since 2005 was performed. Age, sex, location, Breslow thickness, tumor ulceration, regression, Clark level, tumor infiltrating lymphocytes, tumor mitotic rate, microscopic satellite and vascular invasion were included in the analysis. Disease-free (DFS), disease-specific (DSS) and overall (OS) survivals were evaluated by the Kaplan-Meier method and Cox regression analysis.

Results: A series of 141 patients with melanomas thicker than 4 mm were included. Multivariate regression showed a worse prognosis in SLN-positive patients with respect to SLN biopsy-negative patients (DFS, hazard ratio [HR] 2, p = 0.04; DSS, HR 2.2, p = 0.002; OS, HR 2.4, p = 0.02). The observational group was shown to have a worse prognosis than the SLN-positive group but was very similar to the clinically positive group. Immunotherapy with high-dose interferon showed a protective effect (DFS, HR 0.5, p = 0.02; DSS, HR 0.3, p = 0.001; OS, HR 0.3, p = 0.001).

Conclusion: Our data indicate that SLN biopsy and adjuvant interferon should be considered for patients with thick melanomas.