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Most U.S. cancer centers recommend that women begin screening for breast cancer at a younger age and continue screening more frequently than recommended by national screening guidelines, a review of 606 centers showed.

Of the centers that recommended both a start date and screening interval for mammography, more than 80% advised women to begin annual screening at age 40. The U.S. Preventive Services Task Force (USPSTF) recommends mammography every 2 years beginning at age 50, or earlier if warranted by a woman's individual risk/benefit analysis. The American Cancer Society (ACS) recommends an initial mammographic exam between ages 45 and 55, continuing every 1 to 2 years thereafter.

Rates of variation from national recommendations did not differ significantly between National Cancer Institute (NCI)-designated and nondesignated centers, reported Jennifer L. Marti, MD, of Weill Cornell Medicine in New York City, and co-authors in .

"The public advice provided by high-volume breast centers in the U.S. suggests that these centers may prioritize factors not reflected in the data, such as patient and physician preferences, recommendations from specialty (e.g., radiology) societies, concerns about litigation, or possible financial considerations. However, our data could not address causal mechanisms," the authors wrote.

"Optimal screening practices might differ for higher-risk populations (e.g., Ashkenazi Jewish and Black women); this issue requires further study," they added. "Findings from ongoing clinical trials, such as the Women Informed to Screen Depending on Measures of Risk (WISDOM) study, may help to guide discussions with women, assist with decisions about advertising mammography services, and provide standards for appropriate screening intensity."

In an , JAMA editors noted that only 12% of the centers surveyed mentioned the importance of shared decision making between patients and their primary clinicians. They also called out centers that benefit financially from increased screening volume.

"Biennial mammography is preferred because it has benefits similar to those of annual screening but with fewer harms," wrote JAMA Internal Medicine editor Rita F. Redberg, MD, and co-authors Anand R. Habib, MD, and Deborah Grady, MD, all of the University of California San Francisco. "False-positive rates are higher for annual screening compared with biennial screening. False-positive mammography results may produce anxiety along with further diagnostic imaging and invasive testing."

"Breast cancer centers with clear financial benefits from increased mammography rates may wish to reconsider offering recommendations that create greater referral volume but conflict with unbiased evidence-based USPSTF guidelines and have the potential to increase harms among women," they added.

Outside the U.S., mammography every 2 years from ages 50 to 69 represents the norm. Recent updates to the USPSTF and ACS moved the U.S. closer to international standards for screening mammography.

Marti and colleagues hypothesized that specialized breast centers in the U.S. have recommendations that differ from those of national organizations. To investigate they reviewed recommendations published on websites for 606 centers and found that 487 (80.4%) of the centers had recommendations related to screening mammography. Of the remaining 119 centers, 90.8% were non-NCI-designated facilities.

Of the centers with mammography recommendations, 431 (88.5%) specified a starting age for breast cancer screening and 429 (88.1%) had both a starting age and screening interval. The recommended starting age was 40 in 87.2% of cases. Of the remaining centers, 8.1% recommended a starting age of 45 and 4.6% recommended that mammographic screening begin at 50.

Of the 429 centers that specified both a starting age and screening interval, 347 (80.9%) recommended annual screening beginning at 40. The authors reported that 69.8% of NCI-designated centers and 78.1% of nondesignated centers recommended 40 as the starting age for screening mammography (P=0.22). NCI-designated centers more often encouraged women to speak with their physicians about breast cancer screening (17.0% vs 10.8%, P=0.18).

"Earlier screening has both risks and benefits," the authors concluded. "Patient decisions are based on complex individual factors that are best elicited and addressed through shared decision-making. The potential harms of cancer screening are challenging to communicate. Decision aids may help, as women and their physicians tend to of screening mammography."

The American College of Radiology leadership called the study misleading and said it has "serious omissions of fact."

"The claim that facilities offering mammograms to women ages 40 and older are operating counter to recommendations of 'national societies' is misleading at best," according to an ACR statement. "Also, to assert that financial incentives may be driving local site screening recommendations -- with no evidence to back the claim -- is outrageous and insulting to the medical professionals working to save lives from the nation's second leading cancer killer in women."

"The national medical societies most expert in breast cancer diagnosis and care, including the American College of Radiology, Society of Breast Imaging and American Society of Breast Surgeons, recommend that women start getting annual mammograms at age 40. Similarly, the American College of Obstetricians and Gynecologists recommends women start mammography at age 40 and get tested every 1 to 2 years."

The study confirms a indicating that U.S. breast cancer experts "largely do not support delayed or less frequent screening -- as called for by the USPSTF and ACS."

The report by Marti and co-authors showed that most cancer centers follow the recommendations of the National Comprehensive Cancer Network (NCCN), individual physicians, and patient decisions, said Mark A. Helvie, MD, of the University of Michigan in Ann Arbor, a member of the NCCN guidelines panel for breast cancer screening and diagnosis.

Randomized trials of screening mammography versus none have shown a breast cancer-specific mortality benefit for women ages 40 to 49, and the magnitude of benefit is comparable to that of women 50 to 59, said Mark Pearlman, MD, also of the University of Michigan and a member of the NCCN breast cancer screening and diagnosis guideline committee. In terms of years of life saved, younger women get more benefit from screening mammography because they have more years left to live.

Beginning screening at 40 versus 50 carries a potential for more harms -- including mammographic detection of slow-growing cancers that would not prove harmful -- but the issue is inherent to mammography and not age dependent, Pearlman continued. Because screening involves benefits and harms, different groups "draw the line" at different ages.

"However, all groups agree that an individual woman should have access to a conversation about mammography starting at age 40," Pearlman said via email. "Both USPSTF and ACS state that the decision to initiate mammography at age 40 should be a shared one, weighing the benefits ... and risks."

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