Melanoma in kids differs from the adult cancer

The demographics, site of appearance, and outcome of children and teenagers with melanoma differ from the features seen in young adults, according to study findings published in the Journal of Clinical Oncology.

The results suggest melanoma may be biologically different in children and adolescents.

"Melanoma is uncommon in teenagers and rare in younger children," Dr. Julie R. Lange, of Johns Hopkins Medicine, Baltimore, Maryland, and colleagues write. However, differences in this cancer between children and adults are not well understood.
Using the National Cancer Data Base, the researchers compared melanoma cases of children and teenagers who were between 1 and 19 years old with those for patients between 20 and 24 years.

Among the 3,158 children and teenagers, 96.3 percent had melanoma of the skin, the most common site; 3.0 percent had melanoma of the eye; and 0.7 percent had an unknown primary site. Skin melanoma was more common in girls (55 percent) than in boys, and in subjects older than 10 years (90.5 percent).

The authors detected a relationship between the demographics, the site of skin melanomas and age. Younger patients were significantly more likely to be male and nonwhite, to have primary tumors of the head and neck, and to have regional or distant cancer spread.

The patients were followed-up for an average of 59 months. An association was observed between poorer survival and more extensive disease progression and younger age. "Females had significantly better overall survival than males, except in patients aged 1 to 9 years," the investigators found.

Patients between 20 and 24 years with thinner melanomas had significantly better survival rates (96.8 percent) than patients with thicker tumors (82.4 percent)," Lange's team reports. However, within the younger group, survival rates were not significantly different between the thinner and thicker tumors.

The lack of prognostic value of tumor thickness in the young group suggests biologic differences, even more than does the demographic differences compared to the older patients, Dr. Lange and colleagues point out. "More research in the molecular genetics of pediatric melanoma is needed," they conclude.

SOURCE: Journal of Clinical Oncology, April 2007.