Outcome of thick (> 4 mm) node-negative melanomas

Background: Patients with thick melanomas > 4 mm deep are at great risk for regional and distant metastatic disease. Historically, the appropriate management of thick melanomas has remained unclear and there is no consensus in the literature. Many have taken the nihilistic view that surgical intervention to excise regional nodal basins is not justified in light of the poor overall prognosis and risk of occult distant disease. Objectives: To review the outcome of patients with thick node negative melanoma treated at a multidisciplinary academic center Methods: We retrospectively reviewed a database of melanoma patients to identify patients with thick melanomas, > 4 mm, who were either clinically or sentinel node biopsy negative, staged T4N0, stage IIb or IIc. The charts of these patients were reviewed and updated, with a median follow-up of 4 years. Results: We identified 23 patients who fit these criteria. Of these, 18 (78%) remain alive with a median follow-up of 4 years. Five patients died of metastatic disease. Of the 18 surviving patients, 14 remained with no evidence of disease after initial resection of their primary lesions. The majority of the recurrences were non-nodal. Conclusions: The overall survival of patients in our study remains above 75% at median follow-up of 4 years, even with thick initial index tumor depths. Most of the failures were due to hematogenous spread with lymphatic sparing. Tumor biology that may inhibit lymphatic spread could be a target of future investigation.