Start annual mammograms at age 45, according to new breast cancer guideline

By John Murphy, MDLinx
Published October 20, 2015

Key Takeaways

Women with an average risk of breast cancer should begin screening mammography on an annual basis at age 45, according to the American Cancer Society’s (ACS) newly revised breast cancer screening guideline. This updates the ACS’s previous 2003 guideline, which recommended that women begin annual screening at age 40.

At age 55, women can transition to screening mammography every other year but still have the option to continue with annual screening, the new guideline says.

Also, routine screening clinical breast examination is no longer recommended. The guideline was published in the October 20, 2015 issue of JAMA.

“The ACS endorses beginning annual screening mammography at age 45 years and transitioning to biennial screening at age 55 years, while retaining the option to continue annual screening, which some women may elect based on personal preference, clinical guidance, or both,” the authors wrote. “After careful examination of the burden of disease among women aged 40 to 54 years, the guideline development group concluded that the lesser, but not insignificant, burden of disease for women aged 40 to 44 years and the higher cumulative risk of adverse outcomes no longer warranted a direct recommendation to begin screening at age 40 years.”

The ACS decided to update the guideline in light of new evidence from long-term randomized trials and observational studies of population-based screening programs. In addition, the harms associated with screening have taken on greater emphasis in the intervening years.

Accordingly, the ACS’s interdisciplinary guideline development group (GDG) selected the Duke University Evidence Synthesis Group to conduct an independent systematic evidence review of the breast cancer screening literature. In addition, the ACS commissioned the Breast Cancer Surveillance Consortium to update previously published analyses on screening intervals and outcomes. Before submitting the final guideline for publication, the GDG invited 26 relevant outside organizations and 22 expert advisors to participate in an external review of the guideline.

These are their recommendations for breast cancer screening for women at average risk:

  • Women should undergo regular screening mammography starting at age 45.
  • Women 45 to 54 years of age should be screened annually.
  • Women 55 years and older should transition to biennial screening or have the opportunity to continue screening annually.
  • Women should have the opportunity to begin annual screening between the ages of 40 and 44 years.
  • Women should continue screening mammography as long as their overall health is good and they have a life expectancy of 10 years or longer.
  • Clinical breast examination is not recommended for breast cancer screening among average-risk women at any age.

“Most importantly, we know emphatically that breast cancer screening or screening mammography saves lives,” said Kevin C. Oeffinger, MD, GDG co-chair and Director of the Adult Long-Term Follow-Up Program at Memorial Sloan Kettering Cancer Center, in New York, NY. “It is the single best tool that a woman has for preventing a premature death from breast cancer.”

Not ‘one size fits all’

These recommendations “are intended to balance the goal of reducing the burden of breast cancer against the understanding that breast cancer screening is a preventive health intervention applied to the entire eligible population of women, most of whom will not develop breast cancer during their lifetime,” the authors wrote.

The guideline isn’t meant to stand purely to on its own nor be “one size fits all,” but rather is designed for use in the context of a clinical encounter between patient and clinician, the authors noted. “Women should be encouraged to be aware of and to discuss their family history and medical history with a clinician, who should periodically ascertain whether a woman’s risk factor profile has changed. If the woman has an average risk of developing breast cancer, the ACS encourages a discussion of screening around the age of 40 years,” the authors concluded. 

The ACS also recommends that women be informed about risk factors, risk reduction, and the benefits, limitations, and harms associated with mammography screening.

‘Should I have a mammogram?

“Women and clinicians following the ACS guideline may find it confusing to transition from no screening when younger than 45 years to annual screening from ages 45 to 54 years and then to biennial screening,” wrote Nancy L. Keating, MD, MPH, of Harvard Medical School, and Lydia E. Pace, MD, MPH, of Brigham and Women’s Hospital, both in Boston, MA, in an accompanying editorial in JAMA.

Drs. Keating and Pace added, “In communicating with patients, clinicians will have to balance the ACS’ recommendation for more frequent screening against the fact that younger women experience a lower absolute benefit from screening mammography.”

Meanwhile, they advised, physicians should emphasize with average-risk women older than age 40 that there is no single right answer to the question: “Should I have a mammogram?”

“Instead, women should be supported in estimating and understanding their risk of developing breast cancer and articulating their values and preferences so that clinicians can help them make informed decisions,” they wrote. “Ultimately, better screening tools are needed.”

Annual vs. biennial screening

In a related article in JAMA Oncology, the Breast Cancer Surveillance Consortium (BCSC) reviewed the data on annual vs. biennial screening mammography. It found that menopausal status may actually be more important than age when considering the frequency of screening.

In this study, the BSSC looked at a prospective cohort of 15,440 women (ages 40 to 85) whose breast cancer was diagnosed within 1 year of an annual screening mammogram or within 2 years of a biennial screening. The results showed that most women with breast cancer were 50 years or older (85.4%), white (78.1%), and postmenopausal (63.6%).

Premenopausal women diagnosed as having breast cancer following a biennial mammogram were more likely to have tumors with less favorable prognostic characteristics than women diagnosed after annual screening. BCSC defined “less favorable prognostic characteristics” as tumors that are stage IIB or higher, larger than 15 mm in size, and lymph node-positive.

Postmenopausal women (not using hormone therapy) who were diagnosed with breast cancer had similar proportions of less favorable tumors regardless of whether they had a biennial or annual screenings.

“These findings add to the body of evidence that is providing greater confidence in the potential for advising women and their clinicians about screening frequency based on personal risk factors,” the authors concluded.

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