A large number of physicians in the United States are not following evidence-based guidelines for breast cancer screening and continue to recommend screening mammography to women who are more likely to be harmed than to benefit, a national survey has found.

The Breast Cancer Social Networks study (CanS-NET) shows that 81% of primary care physicians recommend screening mammography to women aged 40 to 44 years, even though this is not recommended by the US Preventive Services Task Force (USPSTF) or the American Cancer Society (ACS).

Gynecologists were even more likely to recommend screening for women of all age groups (P < .001).

This was particularly significant in women aged 40 to 49 and those aged 75 and older (P < .05), say Archana Radhakrishnan, MD, MHS, of the Division of General Internal Medicine at Johns Hopkins University, Baltimore, Maryland, and colleagues. Among clinicians who advised screening, 62.9% recommended annual examinations for women aged 40 to 44 years, 66.7% recommended examinations for women aged 45 to 49 years, and 52.3% did so for women 75 years or older.

These new findings "provide an important benchmark as guidelines continue evolving and underscore the need to delineate barriers and facilitators to implementing guidelines in clinical practice," the researchers say in a research letter published online April 10 in JAMA Internal Medicine.

They note that clinicians decide when to begin screening mammography, when to end it, and the optimal time between screenings on the basis of guidelines from the organization they trust the most — even though the recommendations are discordant.

At present, major organizations differ in their recommendations for mammography. In 2015, the ACS revised its guidelines to recommend annual screening from the age of 45 to 55, and continuing every 2 years after that. The USPSTF reissued its guidelines in 2016, recommending that women be screened every 2 years from the age of 50 to 74 years. The American Congress of Obstetricians and Gynecologists (ACOG) guidelines, which gynecologists said they use, recommend annual screening mammography beginning at age 40.

"Different guidelines and professional societies — after reviewing the available evidence — make breast cancer screening recommendations that try to balance the benefits of screening with the potential harms," study coauthor Craig Pollack, MD, MHS, associate professor of medicine at Johns Hopkins, told Medscape Medical News. However, he added in an email, "having mammograms comes with risks, including overdiagnosis, that we need to recognize. It is important to help patients understand these benefits and risks and find the right balance for them."

The findings are "rather dispiriting," say Deborah Grady, MD, MPH, and Rita F. Redberg, MD, from the University of California, San Francisco, writing in an accompanying editorial. (Dr Grady is also the editor of JAMA Internal Medicine.)

The editorialists wonder why more physicians are not following the USPSTF guidelines, since they are "the most evidence-based, transparent, and conflict-free," they comment.

Instead, 88% of physicians "inexplicably trusted other guidelines" and recommended routine mammography for women aged 45 to 50 years, and 67% recommended mammography for women 75 and older, they point out.

About half of the women who undergo 10 mammograms will have a false-positive finding, resulting in repeat mammograms, breast MRI, and often, unnecessary biopsies of indolent tumors "that would never have become bothersome," the editorialists note.

Details of the National Survey

For the CanS-NET study, an email survey was conducted from May to September 2016 in a national sample of 1665 primary care physicians and gynecologists randomly selected from the American Medical Association Physician Masterfile. Primary care physicians included internal medicine and family medicine/general practice physicians who provide primary care or general gynecologic care to women aged 40 years or older.

Physicians were asked whether they recommended routine screening mammograms to women with no family history of breast cancer and no prior breast problems. The researchers focused on women aged 40 to 44 years, 45 to 49 years, and 75 years or older for whom guidelines are discordant. Physicians were also asked which organization's screening guidelines they most trusted and what intervals they recommended between screening examinations.

The response rate was 52%, and the average age of the respondents was 52 years. Slightly more than half of the physicians were male, most with more than 20 years of practice experience. Almost three quarters were primary care physicians.

Some 26.0% of clinicians said they trusted ACOG guidelines, 23.8% said they used ACS guidelines, and 22.9% relied on USPSTF guidelines. Not surprisingly, physicians who trusted the ACS and ACOG guidelines were significantly more likely than those using the USPSTF guidelines to recommend screening to younger women.

When breast cancer screening guidelines change and less screening is recommended, particularly in younger or older patients, it may run counter to patients' prior experiences, Dr Pollack pointed out. "Doctors need to work with patients to help them come to breast cancer screening decisions that are right for them."

Dr Grady and Dr Redberg note that clinicians came up with "the usual excuses" for unnecessary testing, including fear of litigation, the idea that it is better to do something rather than nothing, and the conviction that patients prefer more testing. However, they emphasize, many clinicians believe that caring for patients means going above and beyond what's recommended. Instead, they say, clinicians should be offering patients an informed discussion on the risks and benefits of mammmography.

The authors point out that in Britain, the National Health Service, in its updated patient leaflets, informs women that the risk for overdiagnosis is three times higher than that of avoiding a breast cancer death. In a recent national US survey, however, fewer than 50% of women said their physicians discussed the pros and cons of mammography with them.

The most effective way to decrease unnecessary testing could be to employ an evidence-based payment system, the editorialists suggest. The Affordable Care Act (ACA) mandates coverage of cancer screening in cases in which there is USPSTF grade A or B evidence of moderate or substantial benefit. The ACA is silent regarding coverage of cases in which there is grade D evidence of moderate to high certainty that the harms outweigh the benefits, the editorialists point out.

"We need to reduce the many factors driving the continued use of tests of questionable value or known to be harmful. Ultimately, alternative payment systems that value evidence-based, patient-centered outcomes would improve patient care, choice, and satisfaction while decreasing wasteful spending," the authors write.

The study authors and Dr Grady have disclosed no relevant financial relationshnips. Dr Redberg is editor of JAMA Internal Medicine.

JAMA Intern Med. Published online April 10, 2017. Abstract, Editorial

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