Study Demonstrates Radiation Risk from Digital Screening Mammography Can Be Reduced Further

The risk of radiation-induced breast cancer for women undergoing digital screening mammography can be reduced even more for most women by employing simple changes in screening guidelines.

The findings were published in the January 2016, issue of the Annals of Internal Medicine. The research was part of a comprehensive modeling study, undertaken by the UC Davis School of Medicine (Sacramento, CA, USA) that found minimal risk of radiation-induced breast cancer for most women from digital mammography breast cancer screening. Women with large breasts or those with breast implants, often receive extra screening, and have increased radiation exposure. Larger detectors and other new technologies can help mitigate the risk for these women.

The researchers modeled the risk of women developing radiation-induced breast cancer during their lifetime from digital screening mammography, and as a result dying from the disease. The researchers compared this to the number of breast cancer deaths that were prevented by early detection and found that screening 100,000 women aged between 50 and 74, every two years, prevented 627 deaths. The radiation from such exams, and subsequent additional diagnostics, could cause 27 cases of breast cancer, and four deaths. When women aged 40 to 74 were screened every year, an additional 100 radiation-induced breast cancers occurred, and 12 breast cancer deaths, compared to women aged 50 to 74, who were screened every two years.

The results of the study showed screening mammograms taken every two years, instead of yearly, and starting from age 50, not 40 or 45, would be safer for all women.

Diana Miglioretti, first author of the study, and Biostatistics professor at UC Davis School of Medicine, said, “For most women, the risks are very low. The one group I worry about is women with very large breasts who choose to be screened annually from ages 40 to 74. Most screening mammograms are two views per breast. Some women with large breasts need more than four views for a complete screening examination, increasing their exposure to ionizing radiation. In addition, the dose per view increases with compressed breast thickness, further increasing exposure. For the average woman, having an additional workup for an abnormal screening result offers very small additional radiation exposure. But for some women who have additional mammography views and an image-guided biopsy, the additional workup can account for a quarter of their annual radiation exposure from mammography. For the majority of women, screening mammography is very safe. And if you screen every other year between 50 and 74, that makes it safest.”

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UC Davis School of Medicine