Comments and Response on the USPSTF Recommendation on Screening for Breast Cancer FREE

TO THE EDITOR:

The USPSTF (1) recommended against “routine screening mammography in women aged 40 to 49 years,” writing that the decision should be based on “patient context, including the patient's values regarding specific benefits and harms.” These criteria do not explicitly include risk assessment. Indeed, the recommendation seems to dismiss risk assessment based on “demographic, physical, or historical risk factors for breast cancer,” stating that “none conveys clinically important absolute increased risk for cancer.”

Although age is the most important risk factor over long age intervals, it is not as important as other risk factors at the ages of 40 to 50 years. In 1998, Gail and Rimer (2) suggested that a woman in her 40s should consider mammography screening if her absolute risk was as great as that of a 50-year-old woman without other risk factors. Benefits are believed to outweigh risks in a 50-year-old woman, and Gail and Rimer say the same should be true for a younger woman with similar risk. The ratio of incidence rates of a 50-year-old white woman with no risk factors versus a 40-year-old white woman with no risk factors is 2.46 (2). If the 40-year-old woman has risk factors that increase her risk at least 2.46 times above baseline, she has at least the absolute risk of the 50-year-old woman. Many risk factors, such as having 2 affected first-degree relatives, atypical hyperplasia, and at least 75% dense tissue on mammography, have relative risks that exceed 2.46, as do many combinations of weaker risk factors (2–3). For a 48-year-old woman, risk factors need to increase baseline risk by only 6% to put her at the risk of a 50-year-old woman with no risk factors (2).

Recent data (1) show that screening reduces breast cancer mortality by 15% in women aged 39 to 49 years and by 14% in women aged 50 to 59 years. These data only strengthen arguments (2) that a woman in her 40s with the same absolute risk as a 50-year-old woman has a similar ratio of benefits to adverse effects, such as false-positive results requiring further evaluation. Thus, risk factors in addition to age should be considered when counseling a woman in her 40s on whether to have screening mammography. Of course, “the patient's values regarding specific benefits and harms” should also be considered, as recommended by the USPSTF (1).

Mitchell H. Gail, MD, PhD

Catherine Schairer, PhD

National Cancer Institute

Bethesda, MD 20892