Prognostic factors in melanoma patients with tumor-negative sentinel lymph nodes.

Background: Sentinel lymph node (SLN) biopsy for melanoma results in accurate nodal staging, which guides treatment decisions. Patients with a negative SLN biopsy in general have a favorable prognosis, but certain subsets are at increased risk for recurrence and death. This study aimed to identify risk factors predictive of prognosis in patients with a tumor-negative SLN biopsy for cutaneous melanoma.

Methods: In this post-hoc analysis of data from a multicenter prospective randomized trial, clinicopathologic data of patients with cutaneous melanoma ≥1.0 mm Breslow thickness and tumor-negative SLN were analyzed. Disease-free survival, overall survival (OS), and local and in-transit recurrence-free survival were compared by Kaplan-Meier analysis. Risk factors for worse survival were identified with Cox proportional hazard models.

Results: This analysis included 1,998 patients with tumor-negative SLN with a median follow-up of 70 months. Ulceration, Breslow thickness, nonextremity tumor location, and age ≥45 years were independent risk factors for worse disease-free survival and OS. Breslow thickness and ulceration were the only factors on multivariate analysis that predicted local and in-transit recurrence-free survival. Estimated 5-year OS rates ranged from 55.5 to 95.4% on the basis of the defined risk factors.

Conclusion: There is a wide range of prognosis among patients with tumor-negative SLN. Breslow thickness, ulceration, age, and anatomic location of the primary melanoma are important independent factors predicting survival and recurrence among such patients. These factors can be used to stratify prognosis among patients with tumor-negative SLN to formulate rational long-term follow-up strategies as well as identify high-risk, SLN-negative patients for clinical trials of adjuvant therapy.