Radiation Increases Breast Cancer Risk in Some
A study on breast cancer patients has found that those below age 45 who get radiation treatments are far more likely to contract cancer in the other, or contralateral, breast. The risk was discovered to be especially higher in women with breast cancer in their family history.
The researchers studied some 7,000 women who had been less than 71 years of age when they were diagnosed. All were one-year survivors of breast cancer, and were treated from 1970-86 in the Netherlands.
Although "radiation techniques of today will lead to a lower dose to the contralateral breast than the techniques [from 1970-86] presented in our study, treating clinicians should be aware of the existing dose-response relationship for risk of contralateral breast cancer," said study author Maartje J. Hooning, of the department of medical oncology at Erasmus Medical Center Daniel den Hoed Cancer Center in Rotterdam. "Especially in young women, the radiation dose to the contralateral breast should be kept as low as possible."
While radiation treatment didn't appreciably raise the risk of a new cancer in the other breast, taking the entire 7,000-women group as a whole, when data on younger women were teased out, alarm bells sounded. The study found that the risk of cancer in the opposite breast was increased slightly for women under age 45 % - and for women under age 35, that enlarged risk rose to 78 percent.
There was also increased risk associated with women who got radiation for lumpectomies versus mastectomies. Women under 45 who got post-lumpectomy radiation were 150 percent more likely to contract cancer in their other breast than women receiving post-mastectomy radiation.
Among younger women with a significant family history of breast cancer who had also received post-lumpectomy radiation, there was a 350 percent increased risk of cancer in the opposite breast.