Risks

The benefit of mammography screening outweighs the risk of any harm from the radiation. Currently it is estimated that ionizing radiation needed for a mammogram is lower than the dose of cosmic radiation to which a passenger on an intercontinental flight may be exposed, or a skier on a mountain over 3,000 meters. Use of a low dose gives doctors the ability to repeat the mammogram once a year, beginning after age 40-50 years. A mammogram could be prescribed for women with personal or family history of cancer of the breast or other organs, regardless of their age.

Those patients who have not entered menopause need to make sure they are not pregnant before obtaining a mammogram, due to potential radiation exposure.

• For women who have a breast implant, there is an extremely small chance that the pressure placed on the implant during the mammography will cause a rupture or break. If this occurs, a surgical operation may be needed to have the implant removed.
  
  
• In a very small number of cases, the accuracy of the mammogram is lower than usual.
  
  
  • For women with breast implants, the ability of mammography to detect abnormalities lowers from 92% to 33% because the content of the implant (a gel or a liquid) may block the view and because the scar tissue surrounding the implant tightens.
    
    
  • False-positive readings on a mammogram occur when cancer is not present, but a mammogram is read as abnormal. Most of these false-positive readings will turn out not to be cancer. At all ages, 5-10% of mammograms are abnormal and are followed up with additional testing (a fine-needle aspiration [or sampling], surgical biopsy, or ultrasound).
    
    
  • False-negative findings occur when mammograms appear normal even though breast cancer is actually present and are more common in younger women than in older women.