Starting breast cancer screening at age 50 and undergoing digital mammography every other year may reduce a woman's risk for radiation-induced breast cancer. Due to the frequency and dosing of radiation, women with larger breasts and breast augmentation may face greater risk for breast cancer and breast cancer death. The modeling study is published in Annals of Internal Medicine and was used to inform updated clinical practice recommendations from the U.S. Preventive Services Task Force.
Repeated digital mammography examinations expose women to ionizing radiation that can increase breast cancer risk. Researchers used a computer model to estimate distributions of radiation-induced breast cancer incidence and mortality from digital mammography, taking into considering screening frequency and dose variation among women. They found that annual mammography screening of 100,000 women aged 40 to 74 years might induce 125 breast cancer cases and 16 deaths but avert 968 breast cancer deaths because of early detection. Women with large breasts requiring extra views and higher-than-average radiation doses per view were found to be at increased risk, as were those with breast implants. Beginning screening at a younger age and undergoing annual screening were also associated with an increased risk.
Radiation-induced breast cancer incidence is small relative to the number of breast cancer deaths averted, but is not trivial, according to the authors. They say that women with large breasts who begin annual screening before age 50 have twice the risk for radiation-induced breast cancer than women with small or average-sized breasts because large breasts require extra views for a complete examination. Radiology practices should strive to ensure that large breasts are imaged with large detectors with the fewest numbers of views possible.