Age and interval for screening mammography: Whom do you believe?

The purpose of this article is to help the clinician understand the benefits and limitations of screening mammography in the 40-49 age group. Since the benefit of screening mammography is well established in the literature for the 50-59 age group, comparison of the relevant issues is focused on similarities and differences between these two age groups. The incidence of breast cancer, the effectiveness of mammography, and the growth rates of tumors influence the benefit derived from screening. Available data suggest that mammography is equally effective in both age groups, with similar detection rates of minimal cancer (27 vs. 25%). The difference in estimated annual incidence between the 40-49 and the 50-59 age group is only 8%. Since tumor growth rate seems to be faster in the younger age group, screening should be performed annually, starting at 40 years of age, if it is to provide a benefit.