Mammography May Increase Breast Cancer Risk in Women Under 30

By Ed Martinez

December 7, 2009

The Radiological Society of North America conducted a study, which showed a low-dose of radiation from annual mammography screening may increase breast cancer risk in women with genetic or familial predisposition to breast cancer.

"For women at high risk for breast cancer, screening is very important, but a careful approach should be taken when considering mammography for screening young women, particularly under age 30," said Marijke C. Jansen-van der Weide, Ph.D., epidemiologist in the Department of Epidemiology and Radiology at University Medical Center Groningen in the Netherlands. "Further, repeated exposure to low-dose radiation should be avoided."

Dr. Jansen-van der Weide noted that women who are at high risk for breast cancer need to begin screening at a younger age, because they often develop cancer earlier than women at average risk. However, alternative screening methods to mammography such as ultrasound and MRI should be considered, because the benefit of early tumor detection in this group of women may be offset by the potential risk of radiation-induced cancer.

The researchers conducted their study by performing an analysis of peer-reviewed, published medical research to determine the effect of exposure to low-dose radiation among breast cancer gene mutation carriers, and the effect of radiation on women with a family history of breast cancer. Using data from these studies, the researchers were able to calculate pooled odds ratios to estimate radiation-induced breast cancer risk.

The results showed that among all high-risk women in the study, average increased risk of breast cancer due to low-dose radiation exposure was 1.5 times greater than that of high-risk women not exposed to low-dose radiation. High-risk women exposed before age 20 or with five or more exposures were 2.5 times more likely to develop breast cancer than high-risk women not exposed to low-dose radiation.

Dr. Jansen-van der Weide said that this analysis is based on a small study sample and should be interpreted with caution. She also pointed out that these results apply only to specific high-risk groups of women. Women at average risk were not assessed in this study.

In general, early detection with mammography and prompt treatment can significantly improve a woman's chances of survival. More than 90 percent of women whose breast cancer is found in an early stage will survive. For young, high-risk women and their doctors, it is important to weigh the benefits against any potential risk when making a decision about annual breast cancer screening with mammography.