More mammograms?

The debate continues within the medical community over how beneficial breast cancer screening is for most women. While the U.S. Preventive Services Task Force recommends that women aged 50 to 74 need a mammogram no more than every two years, two new studies suggest that women at increased risk for breast cancer should begin those biennial screenings at age 40. The idea is that, by quantifying these risks, doctors can better advise women when to begin regular screenings.

In the first of two studies on the topic that are featured in the current Annals of Internal Medicine, researchers examined existing data to determine how 13 possible risk factors increased the risk of developing breast cancer. By evaluating data from 66 published articles and from the Breast Cancer Surveillance Consortium, the researchers found that having extremely dense breast tissue and a first-degree relative with breast cancer doubled a woman s risk. Other factors, such as having already had a breast biopsy, having a second-degree relative with breast cancer, or having heterogeneously dense breasts increased a woman s risk by 1.5- to 2-fold. Additionally, current use of oral contraceptives, having never given birth, or having first given birth to a child after age 30, increased a woman s risk by 1.0- to 1.5-fold. The authors assert that a doubling of anticipated risk for breast cancer justifies earlier mammographic screening, i.e. beginning an every-other-year program at age 40. Even a 50 percent increased risk convinced them to make the same recommendation.

But one of the major arguments against early and frequent breast cancer screening is that it may do more harm than good. Thus the second study, authored by a researcher at the Department of Public Health in the Netherlands, used four independent models to investigate this balance of harm and benefit. By comparing mammography screening starting at age 40 versus age 50, the researchers concluded that, for women at twice the average risk for breast cancer, biennial screening beginning at age 40 has more benefits than harms. That is, for such women, the harm to benefit ratio was similar to that of average-risk women aged 50 to 74.

But as ACSH's Dr. Gilbert Ross reminds us, the issue remains complex. The main issue with previous screening recommendations, while only rarely appreciated by media discussions and by the public, he says, is that, while the detection and cure of breast cancer is certainly increased, many of those cancers would never have spread. And many procedures provoked by an abnormal mammogram cause needless harm, generally much greater in consequences than the benefits of detecting the few actual life-threatening breast cancers. However, he does agree that, if a woman s risk of breast cancer is actually twice the average risk, earlier biennial screening is warranted and he also points out the necessity of specialist advice when a woman has the known, high-risk genetic mutations BRCA-1 and 2.