Outcomes in pediatric melanoma: comparing prepubertal to adolescent pediatric patients

The aim of this study was to determine the influence of age on outcome in pediatric melanoma patients and to identify factors associated with positive lymph node status in this population.

A retrospective review of a prospective pediatric melanoma database, using sentinel lymph node biopsy (SLNB), from 1992 to 2006, identified 109 patients with the primary diagnosis of melanoma. Patient age was dichotomized as prepubescent (<10 years of age) and adolescent (≥10-18 years of age). Factors investigated included patient race, sex, and lymph node status and tumor thickness, Spitzoid or Non-Spitzoid histology, radial growth phase, and vascular invasion. The Fisher's exact test was used to compare patient groups. Time-to-event analysis was performed using the Kaplan-Meier method.

There were 25 prepubescent and 84 adolescent patients. Prepubescent patients were more often non-White, had greater tumor thickness, more spitzoid tumors and more vascular invasion. Ten-year overall survival (OS) was 89% and 10-year event-free survival (EFS) was 73%. Among 57 patients who had an SLNB, prepubertal patients had a higher percentage of sentinel lymph node positivity. The odds having a positive SLNB decreased by 13% each year with increasing age. Patients with a tumor thickness ≥2.01 mm had higher odds of having a positive lymph node compared with those patients with a tumor thickness ≤1.0.

This is the largest known study of prepubertal melanoma patients. Although OS and EFS did not differ by age groups, younger ages showed increased risk of lymph node metastasis and thicker tumors. This suggests that the younger pediatric patients may have a disease that differs biologically from that of the older pediatric patients.