Exposure to large amounts of radiation early in life, such as radiation treatment to the chest area for childhood cancer, increases the risk of breast cancer [247-248,255-256].
Women treated with radiation therapy to the chest area for Hodgkin's disease (Hodgkin lymphoma) at a young age have a 3-7 times higher risk of breast cancer than women with Hodgkin's disease who were not treated with radiation therapy .
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.
The amount of radiation given 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 is very high for a woman treated with radiation therapy to the chest area before age 20, but is very small for a woman treated after age 40 .
There are special breast cancer screening recommendations for women treated with radiation therapy at an early age (and other women at higher risk).
Very low doses of radiation (such as from X-rays) don't have much, if any, impact on breast cancer risk [196,257-258].
Although the radiation during mammography can increase the risk of breast cancer over time, this increase is very small [196,257-258].
Studies show the benefits of screening mammography outweigh the risk from radiation exposure, especially for women ages 50 and older [196,257-258].
The limited amount of radiation exposure to airline crews is unlikely to increase breast cancer risk.
Female flight crews tend to have slightly higher rates of breast cancer than other women [259-261]. However, this is likely due to reproductive and lifestyle factors, as well as the night shift work related to the job [259-261].
For example, women who work night shifts for many years have a small increased risk of breast cancer [204-206].
Learn more about night shift work and breast cancer risk.