Boston, MA New Harvard School of Public Health (HSPH) research suggests that routine mammography screeninglong viewed as an essential tool in detecting early breast cancersmay in fact lead to a significant amount of overdiagnosis of disease that would otherwise have proved harmless. Based on a study of women in Norway, the researchers estimate that between 15% and 25% of breast cancer cases are overdiagnosed.
The study appears in the April 3, 2012 issue of the Annals of Internal Medicine.
"Mammography might not be appropriate for use in breast cancer screening because it cannot distinguish between progressive and non-progressive cancer," said lead author Mette Kalager, a visiting scientist at HSPH and a researcher at the Telemark Hospital in Norway. "Radiologists have been trained to find even the smallest of tumors in a bid to detect as many cancers as possible to be able to cure breast cancer. However, the present study adds to the increasing body of evidence that this practice has caused a problem for womendiagnosis of breast cancer that wouldn't cause symptoms or death."
Most women in the U.S. begin having annual mammograms in their 40s or 50s. But recent research suggesting evidence of overdiagnosis has increased debate about the benefits of screening. A number of experts have speculated that new effective treatments for breast cancer play a larger role in saving women's lives than screening doesand have noted that overdiagnosis can cause unnecessary stress and unnecessary medical treatment.
Kalager says the new findings suggest that women should be well-informed not only about the potential benefit from mammography, but also about its possible harmsincluding mental distress, biopsies, surgeries, or chemotherapy and hormone treatments for disease that would never have caused symptoms.
The researchers analyzed data from 39,888 women with invasive breast cancer in Norway, 7,793 of whom were diagnosed durin
|Contact: Marge Dwyer|
Harvard School of Public Health