Mammography may lead to increase in breast cancer for high-risk women

Radiation from mammography screenings may increase the chances of developing breast cancer for women at high risk, according to findings presented Tuesday at the 2009 RSNA meeting.

Recurrent exposure to low-dose radiation can increase chances of breast cancer manifestation in women with genetic mutations or family history of the disease, said lead researcher Marijke C. Jansen-Van der Weide, Ph.D., an epidemiologist at University Medical Center Groningen in the Netherlands. Although screenings are important for women at high risk, those under 30 years of age should be careful when considering mammography, she said.

Researchers drew conclusions from six studies relating breast cancer with radiation screening in high-risk women. They found that, when exposed to low-dose radiation, this population group had about a 1.5 times greater chance of developing breast cancer than did those not so exposed. Women at high risk who have five or more low-dose radiation exposures or exposure before age 20 were 2.5 times more likely to develop cancer. Breast cancer as a result of radiation exposure from mammography screening may take one or even two decades to develop.

However, these results should be taken with caution due to the small sample size of the study, Jansen-Van der Weide said. The findings, she added, apply only to women at high risk.

The study fueled the ongoing controversy on the value of mammography screening for breast cancer. The benefits of screening outweigh the risks found in this study, said Dr. Stephen A. Feig, director of breast imaging at the University of California, Irvine.

"The radiation risk is so low that even a 1% benefit would far outweigh the risk. Most studies show a 30% to 50% benefit of screening," said Feig, who will participate in a panel Wednesday discussing mammography screening guidelines.

Strong evidence from the American Cancer Society supports the benefits of mammography for women over age 40. Reports regarding screening for women under 40 offer conflicting conclusions. Early detection of breast cancer in general increases a woman's chances of survival. More than 90% of women diagnosed in an early stage survive.

Jansen-Van der Weide recommended that women at high risk who are younger than 30 should weigh benefits and costs of screenings carefully. Use of MRI or biannual mammography screening for younger high-risk women may be most beneficial.