USPSTF: Biennial mammography should begin at age 50

The U.S. Preventive Services Task Force has updated its 2002 breast cancer screening guidelines.

The U.S. Preventive Services Task Force has published its updated breast cancer screening guidelines in the Annals of Internal Medicine. In them, the task force recommended against routine breast cancer screening for women aged younger than 50.

Instead, it recommended that biennial screening — instead of annual — should only become routine in women aged older than 50. Women between the ages of 40 and 49 who are at high risk for breast cancer should talk to their physician about the best time to start regular, biennial screening, according to the recommendations.

According to its 2003 recommendations, the American Cancer Society still recommends annual screening beginning at age 40. In a statement, Otis W. Brawley, MD, chief medical officer, American Cancer Society said, "The American Cancer Society continues to recommend annual screening using mammography and clinical breast examination for all women beginning at age 40. Our experts make this recommendation having reviewed virtually all the same data reviewed by the USPSTF, but also additional data that the USPSTF did not consider. When recommendations are based on judgments about the balance of risks and benefits, reasonable experts can look at the same data and reach different conclusions."

Evidence review

In order to update its 2002 recommendations, the USPSTF systematically reviewed published evidence of the efficacy of five screening modalities in reducing mortality from breast cancer: film mammography, clinical breast examination, breast self-examination, digital mammography and MRI.

In addition, the task force commissioned two studies related to breast cancer screening: a targeted systematic evidence review of six selected questions relating to the benefits and harms of screening, and a decision analysis that used population modeling techniques to compare the expected health outcomes and resource requirements of starting and ending mammography screening at different ages and using annual vs. biennial screening intervals.

Using this information the USPSTF released a series of breast cancer screening recommendations. Among them, it concluded that there is insufficient evidence to recommend mammography screening in woman aged older than 75.

In addition, the task force recommended against teaching breast self-examination, as adequate evidence suggests that teaching self-examination does not reduce breast cancer mortality. The researchers also concluded that the current evidence is insufficient to assess the additional benefits and harms of clinical breast examination for women aged 40 or older. This recommendation is a change from the 2002 statement, which suggested mammography screening, with or without clinical breast examination, every one to two years for women aged 40 years or older.

Finally, the task force did not recommend one form of mammography over any other. It concluded that “the current evidence is insufficient to assess additional benefits and harms of either digital mammography or MRI instead of film mammography as screening modalities for breast cancer.”

Dissenting opinion

Constance Lehman, MD, PhD, medical director of radiology and director of breast imaging, Seattle Cancer Care Alliance, released a statement in response to these new recommendations: “Women need a clear message: early detection offers a woman the best chance for a cure, and mammography is essential for early detection of breast cancer. The Seattle Cancer Care Alliance continues to support annual screening mammograms for women beginning at age 40 as does the American Cancer Society. In fact, according to the ACS, 17% of breast cancer deaths in 2006 were among women who were diagnosed between ages 40 and 49.

“Failing to identify those women in their 40s with cancer and having them wait until they are screened at age 50 is a disservice. By then breast cancer can be advanced and more difficult to treat.”

In addition, the National Comprehensive Cancer Network released a statement confirming its continued recommendation of annual clinical breast examinations and mammography for women 40 years and older.

"For women age 40 and over, the benefits of annual breast screening continue to outweigh the risks," said Therese B. Bevers, MD, of the University of Texas M.D. Anderson Cancer Center and chair of the NCCN Guidelines Panel for Breast Cancer Screening and Diagnosis. It its statement the NCCN said that although the interval of screening in women aged 40 to 49 remains controversial, its guidelines clearly recommend annual screenings since mammograms can often detect a lesion two years before the lesion is discovered by a clinical breast examination.

The controversy is not about whether or not mammograms reduce breast cancer mortality, but instead about how best to use the procedure, according to Judy Garber, MD, a breast oncologist and director of the cancer risk and prevention clinic at Dana-Farber Cancer Institute. "These new guidelines will force many groups to reevaluate their recommendations, but we certainly don't want women and their physicians to abandon mammography, which is an imperfect tool, but is the best method we currently have to screen women at average risk of breast cancer."

According to Brawley's statement, "The American Cancer Society acknowledges the limitations of mammography, and we remain committed to finding better tests, and currently are funding a large study to improve the accuracy of mammography. In fact, data show the technology used today is better than that used in the studies in this review, and more modern studies show that mammography is achieving better results than those achieved in these early experimental studies that go back as far as the mid-60s. And as scientists work to make mammography even more effective, the American Cancer Society's medical staff and volunteer experts overwhelmingly believe the benefits of screening women aged 40 to 49 outweigh its limitations." - by Leah Lawrence

Memorial Sloan Kettering Cancer Center's recommendation is to start screening annually at age 40 for women at regular risk for breast cancer and those recommendations are not changing.

I am horrified at this report, which seems like an attempt to generally pull back from breast cancer screening for women. It is an attack on multiple levels with the withdrawal of screening for women in their 40s, a cutback for screening for women 50 and older, and a statement that medical professionals should refuse to encourage women or train women to do any breast self-examination. The data that USPSTF include in their report is essentially unchanged from data that they used seven years ago to encourage women in their 40s to be screened and to encourage annual screening mammography.

In addition, the report affirms that mammography screening done annually saves more lives than screening every other year and affirms that screening with mammography in women in their 40s saves lives. The rationale that they have for withdrawing this level of care from woman is that is causes too many call backs and biopsies. It is a rationale that they say in their assessment of risk/benefit comes out as excessive risk. The benefit is that the likelihood of dying of breast cancer is decreased and I don't see how any of the risks that they state outweighs that benefit.

– David Dershaw, MD
Director of Breast Imaging at Memorial Sloan-Kettering Cancer Center