CHILDHOOD CANCERS are relatively rare—affecting 1% or less of children and adolescents under 20—and are often highly treatable, with 85% of children treated for cancer in the U.S. living five years or more after diagnosis. But those treated for childhood cancers often live with long-term side effects and health risks as adults. According to a recent study, these include a risk of developing melanoma that is more than double the risk in the general population.
The study, published Jan. 8 in the Journal of Clinical Oncology, looked at data from the Childhood Cancer Survivor Study, which followed the health outcomes of 25,716 people first diagnosed with cancer before turning 21. Participants had been treated for cancers including leukemia, lymphoma, bone, brain and central nervous system cancers diagnosed between 1970 and 1999.
Researchers found that 160 of the survivors developed melanoma five years or more after their initial cancer diagnosis. Those who received higher doses of radiation in childhood were even more likely to be diagnosed with melanoma in the following years. Children whose cancers were treated with certain chemotherapies known as alkylating agents or the antibiotic bleomycin, used to treat pediatric Hodgkin lymphoma, were also at higher risk. Overall, survivors of childhood cancers were twice as likely to be diagnosed with an invasive melanoma—one that penetrates into deeper skin layers—as people whose childhoods were cancer-free.
“If you look at the guidelines for taking care of long-term survivors, there was conflicting data about the risk factors for developing melanoma,” says Seth Rotz, a pediatric oncologist at Cleveland Clinic in Ohio and the lead author of the study. While many people have suspected that radiation is a driving factor for increased melanoma risk, he says, “this was the first study to clearly demonstrate that this was the case.”
“This study highlights the importance of ongoing evaluation of effective treatments with fewer adverse effects for childhood cancer,” says Bonnie Teng, the chief scientific officer for the Melanoma Research Foundation in Washington, D.C. She says that some of these treatments, such as high-dose radiation, are no longer current practice in treating childhood cancer. The results, Teng says, could guide efforts to educate patients about skin cancer prevention and screening.
How Different Treatments Affect Melanoma Risk
Melanoma is just one of a range of potential health risks and sensitivities that can appear later in life for childhood cancer survivors. Some survivors experience no adverse effects following their cancers. Others see late side effects long after treatment, including heart problems, fertility issues and lung disease, as well as the emergence of new cancers. Late side effects and risks are linked to the type of treatment people received as children, Rotz says. Someone who had low-dose radiation or whose chemotherapy did not include alkylating agents might be less at risk for melanoma and more concerned with other potential health issues.
For adults who received treatments linked to higher melanoma risk as children, knowing more about the risk can inform their continuing care. Rotz recommends taking sun protection measures and getting new or changing moles checked out promptly, similar to recommendations for people whose melanoma risk is increased because of a history of sun exposure. “If you’re at risk for melanoma, don’t ignore something that pops up on your skin,” Rotz says.
The study’s findings may also point to melanoma as an early warning sign for other health issues for pediatric cancer survivors. Patients who were diagnosed with invasive melanoma after having childhood cancer were twice as likely to die of any cause, including other cancers, as other childhood cancer survivors in the study. “For a lot of these patients, the melanoma was a canary in the coal mine,” Rotz says. “Melanoma can certainly be a life-threatening disease, and it also predicted a higher risk of developing other types of cancers as well.” He recommends that childhood cancer survivors seek out health care providers who are familiar with the long-term risks of cancer treatments to stay on top of their current—and future—health.
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