ORLANDO — Cancer already kills more children aged 1–14 years than does any other disease, and the incidence of childhood melanoma in the United States is on the rise, Dr. Jane M. Grant-Kels said at the annual meeting of the Florida Society of Dermatologic Surgeons.
A 2007 study showed that melanoma accounts for up to 3% of all pediatric malignancies, including about 2% of malignancies in those aged younger than 20 years, and 0.3%–0.4% of malignancies in prepubertal children. The study also showed that melanoma diagnoses are seven times more common between the ages of 10 and 20 years than between 0 and 10 years (J. Clin. Oncol. 2007;25:1363–8).
The National Cancer Institute's Surveillance Epidemiology and End Results database showed an increased incidence of nearly 3% a year during 1985–2003 in those aged 1–19 years. Yet there remains a lack of awareness of the prevalence of melanoma in children. Those who believe that children don't get melanoma are doing their patients an injustice, and such thinking is largely to blame for the fact that diagnosis and treatment are delayed in 40% of childhood melanoma cases, said Dr. Grant-Kels, professor and chair of the dermatology department at the University of Connecticut Health Center, Farmington.
A review of 13 melanoma cases in children younger than age 17 years showed that 85% of the cancers were nodular in type and had a mean thickness of 3.2 mm when diagnosed; 5-year survival was a mean of 59% in the children (J. Am. Acad. Dermatol. 2005;53:816–22). “The lack of awareness and reluctance to diagnose pediatric melanoma can lead to higher incidence of thick melanomas,” wrote the authors.
In another study, a decrease in survival in up to 60% of cases was secondary to a delay in diagnosis attributable to lack of familiarity with pediatric melanoma, lack of vigilance in looking for melanoma in children, and lack of suspicion of melanoma in children.
In light of these findings, it is important to keep in mind that, although melanoma behaves similarly in adolescents and adults, this is not the case in prepubertal children, Dr. Grant-Kels noted.
In one study, melanoma in 33 children aged 14 years and younger was found to be amelanotic in half of the cases. Lesions were raised and resembled pyogenic granuloma in 73% of cases, and they were nodular in type in 27% of cases with a median thickness of 2.5 mm. Most were Clark IV-V lesions. Overall survival at 5 years was about 70% (Pediatrics 2005;115:649–54).
It also is important to keep in mind that childhood melanoma occurs most often in white patients, with only 6.5% of cases occurring in nonwhites, which is a higher percentage than seen in adults. Also, unlike adults, there is a higher predominance of cases in females, with 56%–61% of pediatric cases occurring in girls.
In one study of data from 3,158 patients in the National Cancer Data Base, that figure was 56% in those aged 1–19 years. There was a 90% female predominance among those older than age 10 years, whereas males and nonwhite patients predominated among those younger than age 10 with melanoma (J. Clin. Oncol. 2007;25:1363–8).
That study also showed that younger children tend to present more often with head and neck cancers: Of those aged 1–4 years, 39% presented with head and neck cancers, compared with 12% of those aged 5–19 years. Younger children in the study also were more likely to present with regional and distant metastases and to have poorer survival.
Other studies suggest that the incidence of melanoma is increasing at a faster rate in girls aged 10–19 years than among boys in that age group, which may reflect the popularity of tanning beds among girls, Dr. Grant-Kels suggested.
Some clinical findings that should prompt concern about possible melanoma in children younger than 12 years include a rapid increase in lesion size, bleeding, change in lesion color, nodular growth, pruritus, and lymphadenopathy. In children, 20% of cases occur on the head and neck, and 80% occur on the trunk or extremities, she said.
However, half of melanomas in children arise de novo. About a third arise from congenital melanocytic nevi, and about 20% arise from other melanocytic nevi, including dysplastic nevi, Dr. Grant-Kels said, noting the importantance of having a dermatopathologist review all specimens from pediatric patients.