One-third of breast cancers detected by a mammogram screening might actually not be in danger of spreading or killing the patient, a new study suggests. The study looked at patients in five countries, and found some women might have unnecessary surgery for cancers that were actually harmless; however, since it’s impossible to tell between those that are lethal, and those that aren’t, all of them are treated. “Screening for cancer may lead to earlier detection of lethal cancers but also detects harmless ones that will not cause death or symptoms,” researchers from Denmark’s Nordic Cochrane Centre wrote in the British Medical Journal. “The detection of such cancers, which would not have been identified clinically in someone’s remaining lifetime, is called over-diagnosis and can only be harmful to those who experience it.” However, screening advocates insist it’s crucial to detect cancer cells early enough; one expert told the BBC that screening saves an estimated 1,400 lives in England alone.
One-third of breast cancers harmless
Mammograms may lead to over-diagnosis, study suggests