Breast Cancer Screening with Mammography
There is strong evidence that regular mammographic screening of women aged 50 to 69 years leads to a 25% to 30% reduction in breast cancer mortality. The best evidence of the value of breast cancer screening is derived from the results of the nine major randomized trials that have been published. For example, in one Swedish trial the relative risk of death from breast cancer 12 years after entry was 0.71, and women who were screened with mammography and clinical breast examination were almost 30% less likely to die from breast cancer than were control subjects aged 50 to 69 (Nystrom). Results from other trials for shorter periods, as little as 7 years, are favorable for women 50 years of age or older.
The effectiveness of breast cancer screening with mammography in younger women (age 40 to 49 years) is a subject of great controversy. In January 1997 a National Institutes of Health (NIH) Consensus Panel recommended that women between 40 and 49 years of age be provided with information about the risks and benefits of mammography so that they can make informed decisions concerning screening. This group did not endorse mammography screening of young women (National Institutes of Health Cons0ensus Development Panel). Three months later the American Cancer Society (ACS) issued new guidelines that supported screening women aged 40 to 49 with yearly mammography. Very soon thereafter the National Cancer Advisory Board met and made similar recommendations: women 40 and over should receive screening mammograms every 1 to 2 years. The National Cancer Institute (part of the NIH) then issued a joint statement with the ACS agreeing that on the basis of their review of the data, mammography as a breast cancer screening tool for women 40 to 49 is beneficial (American Cancer Society).
women's health