Screening mammography benefit controversies: sorting the evidence.

Numerous clinical studies have confirmed that screening women age 40 years and older reduces breast cancer mortality by 30% to 50%. Several factors including faster breast cancer growth rates and lower breast cancer incidence among younger women, as well as shorter life expectancy and more comorbid conditions among older women, should also be considered in screening guidelines. Annual screening beginning at age 40 years and continuing with no upper age limit, as long as a woman has a life expectancy of at least 5 years and no significant comorbid conditions, is currently recommended.