The prognostic value of tumor mitotic rate in children and adolescents with cutaneous melanoma: A retrospective cohort study

Abstract

Mitotic rate is a strong predictor of outcome in adult patients with primary cutaneous melanoma, but for children and adolescent patients this is unknown. We sought to assess the prognostic value of primary tumor mitotic rate in children and adolescents with primary melanoma. This was a cohort study of 156 patients who were <20years of age and who had clinically localized cutaneous melanoma. Patients <12years of age were classified as children and those 12 to 19years of age as adolescents. Clinicopathologic and outcome data were collected. Recurrence-free and melanoma-specific survival were calculated. Univariable and multivariable analyses were performed using Cox proportional hazard models. Thirteen of 156 patients (8%) were children. The mitotic rate was ≥1/mm2 in 104 patients (67%) and correlated with increasing Breslow thickness. A positive sentinel node was found in 23 of 61 patients (38%) in whom a sentinel lymph node biopsy specimen was obtained. The median follow-up was 61months. Five-year melanoma-specific and recurrence-free survival rates were 91% and 84%, respectively. Mitotic rate was a stronger predictor of outcome than tumor thickness and was the only factor independently associated with recurrence-free survival. This research was conducted at a single institution and the sample size was small. Mitotic rate is an independent predictor of recurrence-free survival in children and adolescents with clinically localized melanoma.