Screening mammography for women 40 to 49 years of age: a clinical practice guideline from the American College of Physicians.

Breast cancer is one of the most common causes of death for women in their 40s in the United States. Individualized risk assessment plays an important role when making decisions about screening mammography, especially for women 49 years of age or younger. The purpose of this guideline is to present the available evidence for screening mammography in women 40 to 49 years of age and to increase clinicians' understanding of the benefits and risks of screening mammography.