Malignant Melanoma in Older Adults: Different Patient or Different Disease?

Abstract

Objective In this study, we aimed to compare the clinical outcomes between older and younger patients with melanoma and to evaluate for differences in tumor genetic makeup that might explain differences in clinical behavior between older and younger cohorts. Materials and methods A consecutive sample of patients diagnosed with melanoma at a single institution from 1984 to 2019 was categorized by age into younger, middle, and older cohorts. Tumor characteristics, melanoma-specific survival, and recurrence-free survival were assessed while accounting for differential follow-up and death from other causes usingKaplan-Meier analysis with log-rank testing. Results A total of 4378 patients were included in the study. Older patients presented with a higher incidence of T3 and T4 tumors, and a lower incidence of T1 tumors (p<0.001). The same group of patients had a lower nodal positivity at any given Breslow thickness (p<0.01). Melanoma-specific survival was lower for older patients with T2 tumors (p=0.046). There was no difference in recurrence-free survival among all age groups and tumor thicknesses (p>0.05). For patients with a given genetic profile, the melanoma-specific survival and recurrence-free survival were equivalent across ages. BRAF was the most common driver in the younger group, while NRAS and other mutations increased in prevalence as age rose. Conclusions Older adults have decreased melanoma-specific survival for T2 tumors and lower nodal positivity, suggesting a different pattern of metastatic progression. The mutational drivers of cutaneous melanoma change with age and may play a role in the different metastatic progression as well as the differential melanoma-specific survival across all age cohorts.