Screening for breast cancer and mortality reduction among women 40–49 years of age

The recent withdrawal of screening support for women ages 40–49 years is not scientifically supported. The subgroup analyses that have been used severely compromise the statistical power of the trials. None of the trials has the statistical power to be able to provide clear proof of benefit for screening women ages 40–49 years because none of the trials involved sufficient numbers of women in these age groups. Despite having not been designed to evaluate women ages 40–49 years as a separate group, five of the eight randomized, controlled trials have demonstrated mortality reductions for these women that range from 22% to 49%. In addition, data from other nonrandomized trials show that there is no difference in survival for women ages 40–49 years than for women ages 50–59 years. The detection rate for small, early cancers, using modern mammography, is similar for women in both decades. There is no scientific reason to believe that there is a sudden change in detection or cure at age 50 years, or even at menopause. The available data suggest that women ages 40–49 years can benefit from screening, just as can women ages 50–59 years.