Melanoma is rare in children and adolescents; however, its incidence has risen steadily over the past three decades, according to a recent study.1
Researchers from Washington University’s Brown School, the National Cancer Institute, and Dana-Farber Cancer Institute examined data from the SEER (Surveillance, Epidemiology, and End Results) database from 1973 through 2009, investigating first occurrences of melanoma in individuals younger than 20 years old. They found an overall incidence of six cases per million persons and a 2% mean annual increase in incidence during the study period.
“In children between the ages of 0 and 19 years, just 400 to 500 individuals are diagnosed annually in the United States,” said Kimberly J. Johnson, PhD, Assistant Professor at the Brown School and senior author of the study. “Similar to what we’re seeing in adults, rates have increased over the past several decades.”
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The researchers found that melanoma incidence was 1.6 times higher in girls than in boys and increased steadily with age, reaching a peak of 18 per million in 15-to-19-year-olds. However, the most rapid increase in incidence was seen in 10-to-14-year-olds, who experienced a mean annual increase of 2.9%.
The majority of melanomas (77%) were localized, yet the incidence of melanomas that had spread to nearby lymph nodes or tissues grew at an alarming 5.9% per year. The most common sites where melanoma was detected were the face, trunk, legs, and hips. The most rapid increase of melanoma incidence in boys was on the face and trunk, whereas the most rapid increase in girls was on the legs and hips.
Although it is often assumed that the primary cause of melanoma is sun exposure, melanoma was only slightly more common in children and adolescents in regions with high UV levels; interestingly, the most rapid increase was seen in low UV regions, where melanoma incidence increased at a rate of 3.7% per year. Starting in 1985, melanoma incidence actually decreased among 15-to-19-year-olds living in high UV regions.
If exposure to sunlight isn’t driving the increase in melanoma among adolescents, what is? Tanning beds are a possible culprit. Almost one-fourth of adolescents in the United States report having used tanning beds, and more than 10% do so frequently. Indoor tanning facilities are more common in low-UV regions and more often used by girls, which might explain some of the findings of this study.
“Although the exact reasons for this trend are unclear, parents should be vigilant about helping children and adolescents reduce their chance of developing melanoma by practicing sun-protective behaviors and avoiding tanning beds,” said Dr. Johnson.
Awareness of skin cancer has grown among health care providers and the public, therefore more frequent screening also might explain higher rates of diagnosis.
Some evidence suggests that melanoma manifests differently in children than in adults, as seen in a retrospective review of 126 cases of melanoma in patients younger than 21 years old diagnosed at Moffitt Cancer Center in Tampa, FL. Almost one-third of patients had a positive sentinel lymph node biopsy, a higher rate than is typically seen in adults.
“Children with melanoma have higher rates of metastases to sentinel lymph nodes than adults, but they tend to do very well with aggressive treatment,” said Vernon K. Sondak, MD, Chair of the Department of Cutaneous Oncology at Moffitt and senior author of the study.
For patients with a positive biopsy, 5-year recurrence-free survival was 59.5% and melanoma-specific survival was 77.8%, compared with 93.7% and 96.8 % for patients with negative sentinel lymph node biopsy. In this population, 9.1 % of patients 12 to 17 years of age and 17.2 % of patients 18to 20 years of age died from melanoma.
“Despite the higher incidence of nodal metastases, survival is equal to or better than what is reported for adults,” concluded Dr. Sondak. “However, long-term follow-up is necessary in this population since recurrences and deaths are often seen beyond 5 years.”
References
1. Wong JR, Harris JK, Rodriguez-Galindo C, Johnson KJ. Incidence of childhood and adolescent melanoma in the United States: 1973-2009. Pediatrics. 2013;131:846-855.
2. Han D, Zager JS, Han G, et al. The unique clinical characteristics of melanoma diagnosed in children. Ann Surg Oncol. 2012;19:3888-3895.
