CLINICAL STRATEGIES FOR BREAST-CANCER SCREENING - WEIGHING AND USING THE EVIDENCE

When balancing the benefits of screening women for breast cancer again st the harms and costs of such screening, one needs to consider the ri sk far dying of breast cancer, the relative reduction in that risk tha t will result from screening women in different age groups, and the ha rms and costs associated with screening. Seven randomized controlled t rials provide evidence of the relative risk reduction that results fro m screening women in different age groups; other studies estimate the harms and costs of screening. These studies indicate that the benefit of screening, expressed as the absolute number of lives extended per 1 000 women screened, increases with age and that the harm of screening, expressed as the number of follow-up procedures per cancer detected, decreases with age. Thus, the tradeoff between the benefits and the ha rms and costs of screening is better for older than for younger women. Because there is no clear cut-point for determining when benefits out weigh harms and costs, it is important to involve women in discussions of breast cancer screening. The women who most need to be involved ar e those for whom the benefits of screening clearly outweigh the harms and costs and those for whom the benefits and the harms and costs cons titute a ''close call.'' For women in both groups, the physician shoul d routinely raise the issue of screening, first eliciting the patient' s perceptions and then providing information and discussion about the risk for breast cancer and about the benefits and the harms and costs of screening. Furthermore, the physician should encourage the patient to use her own values to weigh the benefits against the harms and cost s, pointing out biases in reasoning and minimizing socioeconomic barri ers. Finally, when the benefits obviously outweigh the harms and costs , the physician should make a clear recommendation for screening.