BREAST CANCER SCREENING GUIDELINES

The updated draft guidelines for breast cancer screening issued by the US Preventive Services Task Force (USPSTF) remain largely unchanged from the 2009 revision.

The update reiterates that mammography screening is most beneficial for women 50 to 74 years of age and that women 40 to 49 years should make individual decisions about screening in partnership with their doctors.

"What these recommendations are reaffirming is that mammography is an important tool in preventing deaths from breast cancer, and that the value of mammography increases with age," said Kirsten Bibbins-Domingo, PhD, MD, vice cochair of the USPSTF. Women 50 to 74 years "are the ones most likely to benefit from it, and we are recommending biennial screening in this age group."

For women 40 to 49 years, the decision to screen should involve a more individualized approach that recognizes the potential benefits and the potential harms.

"We believe that women should be aware of the potential benefits and harms and be guided to make a decision based on their own values and preferences," Dr Bibbins-Domingo told Medscape Medical News.

For women 40 to 49 years, screening mammography can reduce the risk of dying from breast cancer, but the number of deaths averted is much smaller than it is in older women, and the number of false-positive tests and unnecessary biopsies is higher.

In the update, the UPSTF reaffirms its position that, for women older than 75, the evidence is insufficient to assess the benefits and harms of screening mammography.

Clarification Given

When the USPSTF issued its 2009 revision, it was met with criticism from many experts, as previously reported by Medscape Medical News.

The furor was primarily directed at the recommendation against routine screening mammograms for women 40 to 49 years. In fact, a number of organizations, including the American Cancer Society (ACS), the American College of Radiology, and the American College of Obstetricians and Gynecologists, advised physicians and patients to ignore the recommendation.

Dr Bibbins-Domingo pointed out that the USPSTF was never opposed to screening women younger than 50 years; that was a misinterpretation of the recommendations. "We knew that this was an area that would receive a lot of attention, and with this new guideline, we are reaffirming what we said in 2009," she said.

In 2009, the recommendation for women 40 to 49 years was given a grade of C, which many interpreted as a recommendation against mammography screening in this age group, she noted. What it actually means is that there is "moderate certainty of a small net benefit in the population," and that the "decision to screen must be an individual one, made only after a woman weighs the potential benefit against the possible harms," she explained.

The update really just clarifies what the USPTF intended to say, said Therese Bevers, MD, professor of cancer prevention and medical director of the Cancer Prevention Center at the University of Texas M.D. Anderson Cancer Center in Houston.

"It was always just a recommendation against routine screening, but was interpreted to mean that women in that age group shouldn't do it," she told Medscape Medical News. "They are saying that it should be a thoughtful discussion regarding the benefits and harms."

Some people might interpret this update as "backing down," Dr Bevers continued. "They may see it as first they recommended against it and now they are recommending it, but this is what was originally meant all along, and now they have clarified the language."

New Recommendations

There are, however, two new additions in the updated guidelines.

One says that the evidence for 3D mammography as a screening method for breast cancer is currently insufficient to determine its effectiveness. "This is an emerging technology and we found that there just isn't enough evidence at this point. We are calling for more research in that area," said Dr Bibbins-Domingo.

The second says that evidence to recommend a specific screening strategy for women with dense breasts in currently insufficient. "We know that women with dense breast tissue have a higher risk for developing breast cancer, and mammography is not as effective in detecting lesions in this population," she noted. "Technology such as MRI or ultrasound may help improve this, but right now there is not enough evidence to recommend it or not recommend. We are calling for research in this area as well."

Summary of the Draft Recommendations on Screening for Breast Cancer

The recommendation that women 50 to 74 years undergo screening mammography every 2 years is given a grade of B in the updated guidelines. This means that the USPSTF recommends this service and that there is high certainty that the net benefit is moderate or that there is moderate certainty that the net benefit is moderate to substantial.

The decision to start screening mammography before the age of 50 should be an individual one. Women 40 to 49 years who place a higher value on the potential benefit than the potential harms can choose to undergo screening every 2 years. This recommendation is given a grade of C, which means that the USPSTF recommends selectively offering or providing this service to individual patients on the basis of professional judgment and patient preference, and that there is at least moderate certainty that the net benefit is small.

The evidence is insufficient to assess the effectiveness of screening mammography in women 75 years and older. The I statement that this recommendation received from the USPSTF indicates that evidence is lacking, of poor quality, or conflicting, and the balance of benefits and harms cannot be determined.

The statement that evidence is insufficient to determine the effectiveness of 3D mammography as a screening tool for breast cancer also received an I.

For women with dense breasts but negative results on mammogram, evidence to determine the effectiveness of additional screening for breast cancer with ultrasound, MRI, 3D mammography, or other methods is insufficient, and also received an I.

The recommendation against clinicians teaching breast self-examination to patients was not updated and is given a grade of D, which means that the USPSTF recommends against the service. However, the USPSTF believes it is important for women to report lumps and other significant changes they note in their breasts to their healthcare provider.

Differences Remain

Differences in the screening recommendations of various groups remain, but Richard Wender, MD, chief cancer control officer at the ACS, is pleased that the USPTS has clarified their wording. "They have reconfirmed their previous conclusion that there is a benefit for women younger than 50. There was a lot of confusion because of how it was communicated in 2009," he told Medscape Medical News.

The process begins at age 40 — or younger for women at high risk — when physicians should discuss screening with patients. Cancer becomes more common with each passing year, and then peaks when women reach their 60s, Dr Wender explained. "While there still are some differences, the most important point is that we all agree that the discussion should begin at age 40."

He emphasized that there is a lot of overlap in screening guidelines, but it still can be confusing to women. It is key for primary care physicians to be able to explain this to their patients and to work with them to balance the benefits and harms.

Dr Wender reported that the ACS is planning to issue its own updated breast cancer screening guidelines later this year. The ACS currently recommends annual screening starting at age 40 and continuing as long as the woman is in reasonably good health and a candidate for treatment.

The American College of Physicians recommends that, for women 40 to 49 years, screening mammography decisions should be made of the basis of individualized assessment of risk for breast cancer. The American Congress of Obstetricians and Gynecologists, the ACS, the American College of Radiology, and the Society for Breast Imaging all recommend that women begin annual screening mammography at 40 years.

However, the Canadian Task Force on Preventive Health Care recommends not routinely screening women 40 to 49 years with mammography. And it recommends routine screening mammography every 2 to 3 years for women 50 to 74 years.

The American Academy of Family Physicians is in the process of updating its guidelines.

The updated draft guidelines and supporting documents are available for public comment until May 18 on the USPSTF website.