Prognostic Value of Nevus-Associated Melanoma in Patients with Melanoma.

Background: Although most melanomas develop de novo, about 30% are nevus-associated melanomas, where the prognostic value is unclear. Our study aimed to determine whether nevus-associated melanoma is associated with sentinel lymph node (SLN) status and prognosis in patients with melanoma.

Methods: The Sentinel Lymph Node Working Group database, which includes comprehensive clinicopathological and outcome data, was utilized to investigate the association of nevus-associated melanoma with SLN status as well as relapse-free (RFS), melanoma-specific (MSS), and overall survival (OS) using multivariable logistic regression and Cox regression modeling.

Results: A total of 3447 adult patients with a median follow-up of 2.6 years (interquartile range 0.9-6.9) were evaluable. Compared with de novo melanomas, nevus-associated melanomas showed a significant correlation with younger age as well as favorable histological features. The presence of a nevus-associated melanoma was not identified as an independent factor for SLN status (odds ratio 1.06, 95% confidence interval [CI] 0.80-1.41; p = 0.68). Compared with de novo melanomas, nevus-associated melanomas provided independent prognostic information for a favorable RFS (hazard ratio [HR] 0.67, 95% CI 0.53-0.84; p < 0.001), MSS (HR 0.54, 95% CI 0.34-0.85; p = 0.008), and OS (HR 0.42, 95% CI 0.30-0.57; p < 0.001).

Conclusions: Melanomas associated with pre-existing nevi appear to be an independent favorable prognostic factor for recurrence and survival and may potentially be used as a clinical parameter for identifying patients with lower risk of recurrence.