Screening for early breast cancer: Pros and cons

Health benefits and risks of breast cancer screening programs have been both criticized and defended. This paper summarizes and evaluates those arguments, discusses changes that have already occurred, and looks at prospects for further improvement. Early detection of breast cancer can undoubtedly reduce mortality. X‐ray mammography also undoubtedly carries a risk of causing breast cancer at some future time. Both benefits and risks can be estimated. In terms of breast cancer mortality, adding mammography to a program of annual breast examinations of average U.S. women is questionable for women under age 55 but likely to be beneficial for older women. However, the break‐even point is closely related to the average radiation exposure of breast tissue, and might be as early as age 50 in a few centers now using optimum techniques and equipment. For women with below‐average risks of breast cancer the age would be higher, and for a few women with a high probability of developing breast cancer it would be lower. The break‐even point should be significantly exceeded before mammographic screening becomes worth the time, trouble, and other costs. Breast cancer screening programs have been improved significantly since criticisms were first publicized in mid‐1975. Partial improvements include reduction in radiation exposure (at least in some centers), guidelines from the National Cancer Institute (NCI) and the American Cancer Society (ACS) for restricting the screening of women under 50, and changes in the patient consent form signed by screenees in the NCI‐ACS program. There has been a rapid and marked increase in both professional and public awareness of the need to balance the benefits of screening with its risks and costs. Future improvements should further define the optimum design and application of breast cancer screening programs.