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Study: Girls Treated With Radiation For Rare Tumor Face Thirtyfold Increase In Breast Cancer Risk

Gerry Lauzon
A study led by a Seattle scientist found that girls treated with moderate doses of radiation to the chest face drastic increases in breast cancer risk.

A new study finds girls treated with radiation for a rare childhood cancer are much more likely to develop breast canceras young women. The Seattle scientist who led the study said it shows some kinds of radiation therapy can be risky for children even at relatively low doses. 
The study looked at kids with Wilms tumor, a rare kidney cancer diagnosed in just 500 or so North Americans a year. The study has been going on for 45 years, and statistician Norman Breslow of the University of Washington and the Fred Hutchinson Cancer Research Center has been with it all along.

"The last patient enrolled in the study June of 2002. The first patient entered in October of 1969," he said.

Breslow and his team tracked girls who received radiation therapy to their chest to treat tumors that spread there. An alarming number would go on to develop breast cancer.

"Fifteen to 20 percent developed a breast tumor before age 40. The rates were 30 times the general population," he said.

Those who got radiation just to their abdomen had a lower risk, and those who got no radiation had about the same breast cancer risk as the general population.

It is no surprise that radiation therapy increased the chance of developing a secondary cancer, but until now only those who got much higher doses have been told to be extra vigilant.

"This will likely influence breast cancer surveillance recommendations in this population," said Tara Henederson, director of the Childhood Cancer Survivors Center at the University of Chicago Medical Center. She was not involved with the study.

"Childhood cancer survivors have significantly elevated premature mortality as compared to the general population, and after recurrence, second cancers are the leading cause of death. So it is imperative to identify sub-populations of survivors who need to initiate early breast cancer surveillance. This study will help us in identifying one of these populations," she said.

Not many people get Wilms tumor, but the new findings could affect patients with more common diseases like Hodgkin's lymphoma who may get a similar radiation dose.

The study is published in the journal "Cancer."

Gabriel Spitzer is a former KNKX reporter, producer and host who covered science and health and worked on the show Sound Effect.