A genome-wide association study published in the August issue of Nature Medicine has found two tiny genetic variations that can predict which patients with Hodgkin's lymphoma are most likely to develop radiation-induced second cancers years after treatment. Knowing in advance who is at risk could help physicians tailor treatment to reduce the risks for patients who are most susceptible to long-term damage.
Hodgkin's lymphoma is one of the most treatable cancers, with more than 90 percent of patients surviving after a combination of radiation and chemotherapy. But nearly 20 percent of patients treated as children develop a second cancer within 30 years. The younger the patients are when treated and the higher the radiation dose, the greater the risk. This late side effect of treatment is the second leading cause of death for long-term Hodgkin's survivors.
"This finding means we can better identify children who are most susceptible to radiation-induced cancers before treatment begins and modify their care to prevent this serious long-term complication," said Kenan Onel, MD, PhD, associate professor of pediatrics and senior author of the study. "Luckily our options for Hodgkin's are broad enough that we can find ways to control the initial disease without relying on radiation therapy."
"This is also a triumph for genome-wide association studies," he added. "Many previous GWAS studies found multiple genetic differences, with each of them playing only a modest role, with minimal impact on clinical management. In this study, which focused on the interaction between genes and a very specific environmental factorcancer long after radiation therapya small number of genetic differences produced a very big impact."
Onel and colleagues analyzed the genomes of 178 Hodgkin's patients who had been treated between the ages of 8 and 20 with chemotherapy and radiation therapy. Within 30 years after treatment, 96 of them had developed
|Contact: John Easton|
University of Chicago Medical Center