Correlation between prognostic factors and increasing age in melanoma

Background: Age of patients with melanoma varies directly with mortality and inversely with the presence of sentinel lymph node (SLN) metastasis. To gain further insight into this apparent paradox, we analyzed the relationship between age and other major prognostic factors. Methods: The Sunbelt Melanoma Trial is a prospective, randomized study with 79 institutions involving SLN biopsy for melanoma. Eligible patients were 18 to 70 years old with melanoma of ≥1.0-mm Breslow thickness and clinically N0 regional lymph nodes. SLNs were evaluated by serial histological sections and immunohistochemistry for S-100 protein. Results: A total of 3076 patients were enrolled in the study, with a median follow-up of 19 months. Five age groups were examined: 18 to 30, 31 to 40, 41 to 50, 51 to 60, and 61 to 70 years. Trends between age and several key prognostic factors was identified: as age group increased, so did Breslow thickness (analysis of variance; P < .001), the incidence of ulceration and regression, and the proportion of male patients (each variable: χ², P < .001). The incidence of SLN metastasis, however, declined with increasing age (χ²; P < .001). Conclusions: As age increases, so does Breslow thickness, the incidence of ulceration and regression, and the proportion of male patients-all poor prognostic factors. However, the frequency of SLN metastasis declines with increasing age. It is not known whether this represents a decreased sensitivity (higher false-negative rate) of the SLN procedure in older patients or a different biological behavior (hematogenous spread) of melanomas in older patients.