BALTIMORE – Young children with melanoma are more likely to have sentinel lymph node metastases than older children and young adults, according to the results of a new study.
The study also found that thickness and ulceration were strong predictors of sentinel lymph node biopsy (SLNB) in children and young adults with melanoma (Cancer 2011 Oct. 5 [doi:10.1002/cncr.26578]).
Using the 2008 Surveillance, Epidemiology, and End Results (SEER) databases, Euphemia Mu, of Johns Hopkins University, Baltimore, and colleagues analyzed the medical records of 717 children (79 were aged less than 10 years and 638 were aged 10-19) and 1,368 young adults (aged 20-24) who were diagnosed with melanoma between 2003 and 2008.
The researchers gathered demographic and tumor data, and compared tests results from lymph node biopsies based on tumor size, tumor appearance, and age. Median follow-up for all patients was 34 months. Results offered information about:
• Demographics. Younger children with melanoma were more often male (47%) and nonwhite (9%), compared with adolescents (41% male, 2% nonwhite) and young adults (31% male, 1.4% nonwhite).
• Presentation. Melanoma in young children more frequently presented with distant metastases (6%), nodular morphology (10%), and more than 1 mm thickness (40%), compared with tumors in adolescents (1% metastatic, 5% nodular, and 28% more than 1 mm thick) and young adults (2% metastatic, 6% nodular, and 22% with thickness of 1 mm or higher). The proportion with ulceration did not differ significantly among these age groups.
• Likelihood of biopsy. In all, 40% of children and 31% of young adults who had localized disease on examination underwent SLN biopsy. Of those who met the recommendations for SLN biopsy (more than 1 mm in thickness or ulceration), 74% of children and 70% of young adults underwent SLN biopsy. In pediatric and young adult patients, ulceration, histology, thickness, sex, and primary site were correlated significantly with undergoing SLN biopsy.
• Metastases. A total of 25% of children and 14% of young adults who underwent biopsy had SLN metastases. Children whose melanomas were between 1.01 mm and 2.00 mm thick had SLN metastases more often than young adults (24% vs. 4%).
"This finding supports the idea that some melanomas in children may differ biologically from melanomas in adults and should encourage future efforts to investigate the biologic heterogeneity of melanoma," the researchers wrote.
Other characteristics associated with SLN metastases in patients included ulceration (62%) and nodular histology (43%). Overall, children were more likely than young adults to have SLN metastases for all analyzed characteristics (ulceration, histology, thickness, sex, and primary site).
• Prognosis. There was no statistically significant difference in survival between adults and children who tested positive on SLN biopsy. Four out of 64 children (6.3%) and 4 out of 54 young adults (7.4%) who tested positive died vs. 1 of 182 children (0.5%) and 3 of 322 young adults (0.9%) who tested negative.
• Completion lymph node dissection (CLND). Among patients who had negative SLN biopsies, 16% of pediatric and 12% of adult patients underwent CLND, compared with 78% of pediatric patients and 73% of young adult patients who had positive biopsies.
Findings of this study are "a powerful reminder that there’s much about pediatric melanoma that we don’t understand and that, just as is the case with other diseases, children are not small adults, but differ markedly in their response to disease," senior investigator Dr. John J. Strouse, a pediatric hematologist and oncologist at Johns Hopkins, said in a statement.
Study limitations included lack of a centralized review of diagnostic specimens, absence of information regarding mitotic rate, and lack of information about socioeconomic factors, the investigators noted.
Although this study was an important comparison for understanding age-related differences in melanoma characteristics, studies are needed that compare SLN biopsy use and results in pediatric cases with adult cases.
The study investigators made no disclosures.