Evidence of efficacy of mammographic screening for women in their forties

Abstract

Mammography can detect occult invasive cancers in younger women which, if left undetected, would result in grim and early deaths. 3. It is unlikely that mammography will save a higher percentage of breast cancer deaths for women in their forties than for older women. Studies of women in their forties performed to date have in- sufficient power to show such a benefit and, there- fore, do not prove that no benefit exists. 4. It may be possible to show the benefit of mammog- raphy for women in their forties with an enormous clinical trial. Such a trial would be expensive and may well be politically, clinically, and ethically un- feasible. 5. Regardless of whether such a trial is performed, points 1-3 justify screening all women older than age 40. Whether we accept this argument is critically de- pendent on the magnitude of the mortal risk reduc- tion to younger women that will accrue from screening, on the strength of evidence supporting this reduction, and on the risks and costs associated with mammography. It may be helpful to consider the following in making this evaluation.