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Experts divided on mammography guidelines.

Physicians, medical organizations, and federal health officials faced a national uproar last month after the U.S. Preventive Services Task Force issued an update that softened its recommendations on mammographic screening and breast self-examination.

These "major changes" to the task force's breast cancer screening and prevention recommendations "should compel clinicians to examine whether current prevention practices in the United States are consistent with the best available evidence," Dr. Karla Kerlikowske wrote in an accompanying editorial (Ann. Intern. Med. 2009; 151:750-2).

However, the new recommendations, which are a major departure from the group's previous recommendations in 2002, and from recommendations by other major organizations, have drawn mixed reaction in North America and Europe.

In contrast to its 2002 recommendations, the USPSTF now recommends against routine mammography screening in women aged 40-49 years. The previous recommendation was for routine screening every 1-2 years in this age group. Additionally, in older women aged 50-74 years, the new recommendation reduces the frequency of screening mammography from annual to biennial (Ann. Intern. Med. 2009;151:716-26).

The new guidelines recommend against breast self-examination, whereas the previous guidelines cited insufficient evidence. The evidence for clinical breast examination continues to be assessed as insufficient.

Similarly, insufficient evidence is cited to assess digital mammography or magnetic resonance imaging--the first time USPSTF recommendations have considered these screening tools.

The USPSTF guidelines were updated using evidence from two studies commissioned by the task force and reported in the same issue of the Annals of Internal Medicine. One study, funded by the Agency for Healthcare Research and Quality, is an updated systematic review of screening mammography randomized controlled trials (Ann. Intern. Med. 2009;151:727-37).

It concludes that mammography screening reduces breast cancer mortality by 15% for women aged 39-69 years, and that both false-positive results and additional imaging are common. Among the studies reviewed, "rates of overdiagnosis vary from less than 1% to 30%, with most from 1% to 10%," noted investigator Dr. Heidi Nelson of Oregon Health and Science University, Portland.

The other study, by the Cancer Intervention and Surveillance Modeling Network (CISNET), which was funded by the National Cancer Institute, used estimates of screening outcomes for a range of screening strategies at different frequencies and ages of initiation and cessation (Ann. Intern. Med. 2009;151:738-47). This study concluded that "biennial intervals are more efficient and provide a better balance of benefits and harms than annual intervals."

"This change is overdue," said Donald A. Berry, Ph.D., one of the coauthors of the CISNET article and a biostatistician at the University of Texas M.D. Anderson Cancer Center, Houston. "Consistent with the attitude in U.S. medicine that if some is good then more is better, we've opted hell-bent for more--with no evidence," he said in an interview. "The standard in Europe is biennial screening. In the United States we tend to go overboard when it comes to medicine, and screening is an example."

The effect of the CISNET analysis was to allow "the harms of additional screening to come screaming to the top," he said. "The harms of doubling the screening interval come close to being halved while the benefits are nearly unaffected."

But, the American Cancer Society, which has been at the center of a recent media uproar ("Cancer Screening Critique Causes Firestorm in Media," Nov 1, 2009, p. 2) over rumors of a similar softening on breast and prostate cancer screening, was quick to distance itself from the new USPSTF recommendation.

"The American Cancer Society continues to recommend annual screening using mammography and clinical breast examination for all women beginning at age 40," ACS Chief Medical Officer Otis W. Brawley said in a statement. "Our experts make this recommendation having reviewed virtually all the same data reviewed by the USPSTE but also additional data that the USPSTF did not consider."

Central to the differences between the ACS and USPSTF guidelines is the 40- to 49-year-old age group, for whom the USPSTF describes the benefits minus harms of screening mammography as small. "The decision to start regular, biennial screening mammography before the age of 50 years should be an individual one and take patient context into account, including the patient's values regarding specific benefits and harms," the USPSTF said.

The ACS disagreed in a statement: "The USPSTF says that screening 1,339 women in their 50s to save one life makes screening worthwhile in that age group. Yet [the] USPSTF also says screening 1,904 women aged 40-49 in order to save one life is not worthwhile. ... The American Cancer Society's medical staff and volunteer experts overwhelmingly believe the benefits of screening women aged 40-49 outweigh its limitations."

The American College of Obstetricians and Gynecologists maintains its current advice that women in their 40s continue mammography screening every 1-2 years and women aged 50 or older continue annual screening.

Eleven health organizations, including the American Academy of Family Physicians, sent a letter Dec. 2 supporting the USPSTF guidelines to Rep. Frank Pallone (D-N.J.), who chairs the Health subcommittee of the House Energy and Commerce Committee.

But the federal government is distancing itself from the USPSTF recommendations. Health and Human Services Secretary Kathleen Sebelius issued a statement that said, "The [USPSTF] is an outside independent panel of doctors and scientists who make recommendations. They do not set federal policy and they don't determine what services are covered by the federal government .... The Task Force has presented some new evidence for consideration but our policies remain unchanged. Indeed, I would be very surprised if any private insurance company changed its mammography coverage decisions as a result of this action."

The new USPSTF guidelines are "'a step in the right direction," according to Dr. Peter Gotzsche, director of the Nordic Cochrane Centre in Copenhagen. "'It is clearly a waste of resources to recommend annual mammograms, as the American Cancer Society still does," he said in an interview.
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Author:Johnson, Kate
Publication:Family Practice News
Geographic Code:1USA
Date:Dec 1, 2009
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