Jorgensen and colleagues say that far too many women are receiving false positive results from mammograms. In fact, the risk of a false positive after 10 mammograms is 49%, they wrote. That means "19% of women who do not have breast cancer would have undergone biopsy after 10 mammograms."
They continued, "Substantial overdiagnosis and overtreatment increases mortality (e.g., from heart disease and lung cancer caused by radiation therapy). The net effect of screening on all-cause mortality, if any, must be minimal, even if screening still had some effect on breast cancer mortality today (which is doubtful.)"
In defense of the Swedish study's conclusions, however, Daniel B. Kopans, MD, of the Department of Radiology at Massachusetts General Hospital, Robert A. Smith of the American Cancer Society and Duffy wrote a rebuttal.
"The latest challenge to screening mammography has been the argument that screening leads to the diagnosis of a large number of breast cancers that, if left undiscovered, would never become clinically evident and thus would never become potentially lethal," Kopans and colleagues wrote.
They "recognize that there are almost certainly some breast cancers that will never be lethal," and that many women will be treated with systemic therapy without clinicians knowing specifically who will benefit and who won't.
But in conclusion, they wrote, "early detection, although not perfect, has been repeatedly demonstrated to reduce deaths from breast cancer and that the risk of overdiagnosis is small compared with this benefit."