Current controversies in breast cancer screening

Multiple large-scale, randomized controlled trials throughout the world have demonstrated screening mammography significantly reduces a woman's risk of dying from breast cancer. Despite the known mortality reduction, the perceived harms of mammography are weighed against the known value. Multiple national guidelines have moved away from recommending all women have annual screening mammograms beginning at age 40. Instead, many now encourage women at average risk for developing breast cancer to engage in shared decision-making with their providers, carefully weighing the perceived harms against the known benefits of mammography. These factors should be incorporated into the decision about when to begin and how often to screen. This paradigm shift has been particularly controversial as it relates to women in the 40-49-year age group, considering their incidence of breast cancer and therefore derived benefit of screening is lower, yet the breast cancers that do occur tend to be more aggressive and often require intensive therapy. Thus, debates ensue over the appropriate age at which to begin screening for breast cancer, how often screening should occur, and when to stop.