Study: Women Treated for Thyroid Cancer Have Increased Risk of Breast Cancer

Women who are treated for thyroid cancer, particularly premenopausal white women, appear to be at increased risk of breast cancer, according to researchers at the M.D. Anderson Cancer Center in Houston.

Overall, women with thyroid cancer had an 18 percent higher-than-average risk of developing breast cancer up to 20 years later. Premenopausal white women were 42 percent more likely to develop breast cancer, according to the study published in the journal Cancer.

"Women with a history of thyroid carcinoma have a greater than expected risk of developing breast carcinoma," wrote the researchers. "This risk is most pronounced in premenopausal white women."

Women with breast cancer, however, were not at a higher risk of developing thyroid cancer, and black women with thyroid cancer were not found to be at a higher risk of breast cancer, according to the study's findings.

Researchers speculate that radioactive iodine used in the treatment for thyroid cancer may be linked to the development of breast cancer.

Other sources: Cancer