Melanoma risk doubles among childhood cancer survivors
Key takeaways:
- Childhood cancer survivors are twice as likely to develop melanoma as the general population.
- Those diagnosed with invasive melanoma had increased risk for death.
Childhood cancer survivors are more than twice as likely to develop melanoma as the general population, according to findings published in Journal of Clinical Oncology.
Childhood cancer survivors diagnosed with an invasive form of melanoma exhibited a twofold increased risk for death.
“We have known for some time that childhood cancer survivors were at higher risk for melanoma compared with the general population but, to date, have not been able to tease out the relevant risk factors for melanoma,” Seth J. Rotz, MD, a pediatric hematology oncology and blood and marrow transplantation specialist at Cleveland Clinic and assistant professor in the department of pediatrics at Case Western Reserve University School of Medicine, told Healio. “Doctors have long suspected a potential relationship between therapeutic radiation and melanoma, but this had never been proven because large enough patient populations with granular data were not available.”
Rotz and colleagues used data from 25,716 patients in the Childhood Cancer Survivor Study to assess incidence of, risk factors for and outcomes after melanoma.
The cohort included individuals aged younger than 21 years at time of diagnosis of leukemia, lymphoma, central nervous system cancer, renal cancer, neuroblastoma, rhabdomyosarcoma or bone cancer.
Researchers determined 160 survivors developed 177 melanomas (110 invasive, 62 in situ cutaneous, five ocular).
Results showed a 40-year cumulative melanoma incidence of 1.1% (95% CI, 0.9-1.4) in the cohort. This increased to 1.5% (95% CI, 1-2.1) for the subgroup who received a cumulative radiation dose of at least 40 Gy.
Researchers calculated a standardized incidence ratio for invasive skin or ocular melanoma of 2 (95% CI, 1.6-2.4) compared with the general population.
Three factors appeared associated with increased risk for cutaneous melanoma: cumulative radiation dose of 40 Gy or more to the corresponding body region of the melanoma (HR = 2; 95% CI, 1.1-3.7), cumulative cyclophosphamide equivalent dose of at least 20,000 mg/m2 (HR = 1.9; 95% CI, 1.1-3.6) and bleomycin exposure (HR = 2.2; 95% CI, 1.2-4.1).
Invasive melanoma at any location increased risk for death (HR = 2.4; 95% CI, 1.7-3.3).
Researchers acknowledged study limitations, including small patient numbers and the inability to account for common melanoma risk factors such as UV radiation exposure, skin pigmentation, genetic predisposition and family history.
“Now that we know the risk factors, we should be able to clinically understand which patients are at higher risk,” Rotz told Healio. “We need to determine if specific screening approaches (eg, annual dermatologist skin exam) can help detect melanoma sooner in these patients and if that ultimately can prevent advanced melanoma ... or even death.”
For more information:
Seth J. Rotz, MD, can be reached at rotzs@ccf.org.
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