Mammography may increase cancer risk for some women

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Women who have a known genetic or hereditary risk of developing breast cancer are advised to get regular mammograms, often beginning as early as age 20. But the benefits of such vigilance may be offset by the harm from receiving so much radiation, according to research presented today at the annual meeting of the Radiological Society of North America.

Researchers conducted a review of previous studies to look at whether low-dose radiation from mammography affects breast cancer risk among high-risk women. They found six studies that addressed this question and, using data from those studies, they were able to estimate the odds for radiation-induced breast cancer risk. They found that, among all high-risk women, the average increased risk of breast cancer due to low-dose radiation was 1.5 times greater compared with high-risk women not exposed to radiation. High-risk women exposed before age 20 or who those who had five or more exposures were 2.5 times more likely to develop breast cancer than high-risk women not exposed to low-dose radiation. Radiation exposure is thought to be more dangerous in younger women than older women because of higher rates of cell growth among younger women

Women at high risk for breast cancer are often urged to undergo both mammography and breast MRI each year from the ages of 25 to 65, said the lead author of the study, Dr. Marijke C. Jansen-van der Weide, an epidemiologist with the Department of Epidemiology and Radiology at University Medical Center Groningen in the Netherlands. High-risk women and their doctors may want to consider alternative screening methods, such as ultrasound and MRI, she said.

‘It’s very important for high-risk women to be screened,’ she said in a telephone interview. ‘But for young high-risk women it’s important to weigh the benefits and risks of mammography screening with their doctors because there are alternative screenings strategies like MRIs.’

MRIs may be underutilized for these women. There are drawbacks to these methods, however. MRI’s have higher rates of false positives, are more expensive and more time-consuming.

The study included small numbers of women, Jansen-van der Weide noted. Larger studies should be conducted to better understand the radiation risks conferred by mammography.

-- Shari Roan