Clinical practice. Mammographic screening for breast cancer

Abstract

A 44-year-old woman who is a new patient has no known current health problems and no family history of breast or ovarian cancer. Eighteen months ago, she had a normal screening mammogram. She recently read that mammograms may not help to prevent death from breast cancer and that “the patient should decide.” But she does not think she knows enough. She worries that there is a breast-cancer epidemic. What should her physician advise?

Figure 1. Chances of False Positive Mammograms, Need for Biopsies, and Development of Breast Cancer among 1000 Women Who Undergo Annual Mammography for 10 Years

All numbers are rounded. The numbers for 10-year rates of false positive mammograms and breast biopsies come from a single study in which, overall, the rate of false positive mammograms was 6.5 percent, and the rate may be different in other settings. Data on the development of breast cancer are broken down further in Figure 2.

Figure 2. Chances of Breast-Cancer–Related Outcomes among 1000 Women Who Undergo Annual Mammography for 10 Years

All numbers are rounded. The numbers for the incidence of invasive breast cancer and ductal carcinoma in situ, as well as the number of women whose lives are saved by treatment (those surviving at least 20 years after the first diagnosis of breast cancer) regardless of screening, were calculated on the basis of data from the Surveillance, Epidemiology, and End Results program.^, The numbers of women whose lives are saved because of screening (those surviving at least 15 years after diagnosis) were calculated on the assumption of a reduction of 20 percent in mortality from breast cancer among women 40 to 49 years of age and a reduction of 30 percent among women 50 to 69 years of age; these numbers are approximate.