Exposure to large amounts of radiation early in life—such as the atomic bomb explosions in Japan or radiation treatment for childhood cancer—is linked to an increased risk of breast cancer [53-59].
Radiation treatment for Hodgkin’s disease or other cancers
Women treated with radiation therapy for Hodgkin's disease at a young age have about three to seven times the risk of breast cancer compared to women with Hodgkin's disease who were never treated with radiation therapy [53-56,58]. Although radiation therapy increases the risk of breast cancer later in life, its benefits for the treatment of Hodgkin's disease or other cancers far outweigh this risk.
Amount of radiation and age at exposure
The amount of radiation and a person’s age at the time of the treatment for Hodgkin’s disease or other cancer play important roles in breast cancer risk. In general, the more radiation a person is exposed to and the younger the age at exposure, the greater the risk. For example, the risk of breast cancer from radiation treatment is very high for a woman exposed before age 20, but is very small if she is exposed after age 40.
Due to their increased risk of breast cancer, women treated with radiation therapy at an early age have special screening recommendations. Learn about these breast cancer screening recommendations.
Mammography and X-rays
Very low doses of radiation—such as from X-rays—do not have much, if any, impact on breast cancer risk. While the radiation during mammography can increase the risk of breast cancer over time, this increase is very slight. Studies show that the benefits of screening mammography outweigh the risks, especially for women aged 50 and older [60-63].
Learn more about mammography.
Occupational exposure to radiation
It is unlikely that the limited radiation female airline crews are exposed to increases breast cancer risk. Although female flight crews do not have higher rates of breast cancer death, they do tend to have slightly higher rates of breast cancer. This is likely due to reproductive and lifestyle factors, as well as the shift work related to the job [64-65]. Women who work night shifts for many years have a small increased risk of breast cancer (learn more) [66-70].