Background: We postulated that the worse prognosis of melanoma with advancing age reflected more aggressive tumor biology and that in younger patients the prognosis would be more favorable. Materials and Methods: The expanded AJCC melanoma staging database contained 11,088 patients with complete data for analysis, including mitotic rate. Results: With increasing age by decade, primary melanomas were thicker, exhibited higher mitotic rates, and were more likely to be ulcerated. In a multivariate analysis of patients with localized melanoma, thickness and ulceration were highly significant predictors of outcome at all decades of life (except for patients younger than 20 years). Mitotic rate was significantly predictive in all age groups except patients <20 and >80 years. For patients with stage III melanoma, there were four independent variables associated with patient survival: number of nodal metastases, patient age, ulceration, and mitotic rate. Patients younger than 20 years of age had primary tumors with slightly more aggressive features, a higher incidence of sentinel lymph node metastasis, but, paradoxically, more favorable survival than all other age groups. In contrast, patients >70 years old had primary melanomas with the most aggressive prognostic features, were more likely to be head and neck primaries, and were associated with a higher mortality rate than the other age groups. Surprisingly, however, these patients had a lower rate of sentinel lymph node metastasis per T stage. Among patients between the two age extremes, clinicopathologic features and survival tended to be more homogeneous. Conclusions: Melanomas in patients at the extremes of age have a distinct natural history.
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