Factors affecting the estimates include the proportion of high-risk women screened, the sensitivity and specificity of the mammography technique, the interval between examinations, and the cost of each mammogram. Screening with either mammography alone or in combination with physical breast examination can reduce the disease burden from breast cancer by reducing both morbidity and mortality. Differences in sensitivity of the screening tests might explain some of the differences in mortality reduction in different screening trials. Although data are not available on mortality reductions obtained from routine mammography screening that are not part of research programs, preliminary data from extensive screening programs are available from Australia, the Netherlands, and Scandinavia. Overall results indicate that acceptable levels of sensitivity and specificity of mammography can be achieved and suggest that these programs may result in a future reduction of breast-cancer mortality.
Age is considered the only practical criterion on which to base screening guidelines.
Because of reduced sensitivity of screening and a lower incidence of breast cancer among younger women, the cost-effectiveness of screening younger women is less favorable than for older women. Mammography screening trials have not convincingly demonstrated mortality reduction among women less than 50 years of age. However, if more sensitive screening methods are developed, the cost-effectiveness of screening younger women might be improved. Effective tracking and reminder systems must be an integral part of breast-cancer screening programs. Mammography can be highly sensitive and specific, and can be provided at reasonable cost for widespread screening of asymptomatic women.