Sentinel lymph node biopsy in pediatric and adolescent cutaneous melanoma

Objectives Melanoma is rare in pediatric patients with a rising incidence in adolescence. This has precluded valid comparisons between young patients and adults undergoing sentinel lymph node biopsy (SLNB) for localized melanoma of intermediate thickness. This study utilises the large Sydney Melanoma Unit (SMU) database to clarify this issue.

Methods Clinical and pathologic information on pediatric / adolescent AJCC Stage I and II melanoma patients aged <20 yrs who underwent SLNB at SMU between Jan 1993 -Nov 2008 was reviewed. SLNB positivity rates and outcomes were compared with adult SMU patients.

Results In 63 pts ( 31 F, 32 M) the median age was 16.2yrs (range 3.5-19yrs) only 7 were aged <10 yrs. The primaries were located on trunk (33%), head and neck region (29%), legs (21%) and arms (18%). Median tumor thickness was 1.9mm (range 0.6-5.2mm) and SLNB positivity rate was 18/63 (29%), although tumors tended to be thicker (median 3.1mm) and SLNB positivity rate higher (3/7; 43%) in pts <10years.There was 1 FN.The SLN positivity in the adult population was 17%. In 10 pts with atypical or ambiguous primary melanocytic lesions 3 had positive SLNB. 16 of 17 patients underwent immediate completion lymph node dissection (CLND) and 2 had non-SLN metastases (12.5%). Only 0.6% of 343 nodes removed at CLND contained metastases. 3(20%) of 15 SLNB positive patients with follow-up data (median follow-up period of 60 months, range 5-143 months) died from melanoma.

Conclusions Although the SLNB positivity rate is higher in pediatric and adolescent melanoma patients than in adults (29% versus 17% respectively), non-SLN positivity and melanoma-specific death rates were low.