Nevus-associated acral melanoma has lower risk of recurrence and mortality than de novo acral melanoma: A multicenter, retrospective analysis of 482 patients.

Background: It is unknown whether acral melanomas (AM) associated with pre-existing nevi have similar risk to other acral melanomas.

Objective: To compare risk of recurrence and death between AM associated with pre-existing nevi and de novo AM.

Methods: We conducted a multicenter retrospective cohort study involving patients diagnosed with AM between February 2011 and November 2022.

Results: 164 patients (34.0%) had nevus-associated acral melanoma (NAAM). NAAM has lower risk of recurrence (HR 0.69, 95% CI 0.52-0.91, P = 0.008) and mortality (HR 0.53, 95% CI 0.37-0.76, P < 0.001) than de novo acral melanoma (DNAM). The five-year recurrence-free survival (RFS) was 55.1% for NAAM compared to 42.3% for DNAM. The five-year overall survival (OS) was 75.1% for NAAM and 63.2% for DNAM. Multivariate analyses identified Breslow thickness, nevus association, and sentinel node status as independent predictors of RFS. Age, Breslow thickness, nevus association, lymphovascular invasion, ulceration, and sentinel node status were independent predictors of OS.

Limitations: The study's limitations included its retrospective design and missing data.

Conclusion: Patients with nevus-associated AM had significantly better RFS and OS compared to those with de novo AM. Nevus association was an independent prognostic factor for both RFS and OS.