Adverse effects

Adverse effects of mammographic breast screening include:

• radiation risk - estimated that one extra breast cancer develops each year in women over 50 years, after a latent period of up to 10 years, for each million women screened
  
  
• psychological and physical morbidity - mainly associated with false-positive screens - about two thirds of screen detected abnormalities are found to be unimportant on further mammography or ultrasound scanning
  
  
• diagnosis of cancer that would not have become symptomatic during the woman's lifetime - in breast cancer, the natural history is not fully understood nor is there a clearly recognisable early stage of the disease. This carries the risk that some women will be subjected to further investigation and treatment which is unnecessary
  
  
• resource costs - both real and opportunity costs of the screening programme
  
  
• false-negatives - approximately 5% of cancers in women over the age of 50 years are mammographically invisible