American Cancer Society Recommends Fewer Mammograms

In a controversial move, the American Cancer Society is recommending women who aren’t at high risk for developing breast cancer start yearly mammograms at age 45 and switch to every other year at age 55. They should continue getting the test every other year for as long as they are in good health and are expected to live 10 or more years.

But the guidelines also say women should still have the option of earlier or more frequent mammograms. They also suggest doing away with clinical breast exams, when a doctor feels for lumps in the breast. The group made these recommendations based on dozens of studies, including a new one from the University of California–Davis that was published online Oct. 20 by the Journal of the American Medical Association Oncology.

Background and Goals

A mammogram is a test that uses x-rays to look at the breasts. When a woman without any symptoms has one, it’s called a screening mammogram. If a radiologist finds something suspicious on the mammogram, he or she may order other tests, including a biopsy, which can diagnose breast cancer. For years, women have been told to start getting screening mammograms every year starting at age 40.

But in 2009, the US Preventive Services Task Force started recommending that women get screening mammograms every other year, starting at age 50 and stopping at age 74. The task force was concerned about the extra radiation, tests and anxiety that some women experience when a mammogram finds something that looks abnormal, but is actually harmless. These drastic changes concerned many people and many organizations, including Living Beyond Breast Cancer.

The American Cancer Society looked at a number of studies when making their decision, including the UC Davis study, whose results were released the same day the new guidelines were announced. Researchers with that study wanted to know how getting a screening mammogram every year or every other year affected the aggressiveness of a tumor at diagnosis, and what effect age and menopausal status had.

Design

The UC Davis study took place from 1996 to 2012. It involved 15,400 women ages 40 to 85 who were diagnosed with breast cancer within 1 year of an annual screening mammogram or within 2 years of a screening mammogram given every other year. The age and menopausal status of the group was:

• 85.4 percent age 50 or older
• 63.6 percent postmenopausal

The study labeled tumors as either less favorable, linked to a person doing poorer during the course of the disease, or more favorable, linked to a person doing better during the course of the disease. Tumors were called less favorable if they had one of more of these factors:

• Stage IIB or higher
• Bigger than 15 millimeters
  • (Breast tumors range in size from smaller than 10 millimeters to larger than 50 millimeters)
• Spread to the lymph nodes

Results

The study found that among premenopausal women:

• Mammograms done every other year were associated with a significantly higher risk of being diagnosed with less favorable tumors

But among postmenopausal women:

• Whether a mammogram was done every year or every other year didn’t affect how favorable the tumor was (as long as the woman was not taking hormone replacement therapy, medicines to help with symptoms of menopause)

The researchers say this shows menopausal status, not age, should determine how often a woman gets mammograms. The average age of menopause in the United States is 51.

When forming their new guidelines, the American Cancer Society looked at dozens of other studies as well. These studies added to their confidence that, among average-risk women, yearly screening is best for women aged 45 to 54, many of whom are still premenopausal. They say screening every other year is best after age 54. (By this age, the vast majority of women will have gone through menopause.) They also concluded from some of these studies that there is no evidence to suggest clinical breast exams performed by doctors save lives.

Limitations

The UC Davis study was not a randomized clinical trial, where participants are assigned to one action or another by a computer to avoid bias. It is possible women who knew they were at higher risk for breast cancer chose to have mammograms more often than women with fewer risk factors. This could have affected the results.

What This Means for You

Because these guidelines are so different from other guidelines, you may find them confusing. You may feel that annual mammograms are important or worry that your insurance company will stop paying for them.

But if you have a history of breast cancer, or have a family history or genetic mutation that makes breast cancer more likely, you are not in the average-risk group that these guidelines address. And experts say this change is unlikely to stop insurance companies from paying for yearly mammograms for women who are 40 or older. Call your insurance company to ask about how it covers screening mammograms.

Still, if you had breast cancer that was caught by a mammogram, you may have a strong, negative reaction to these guideline changes.

There are several groups in the U.S. that make breast cancer screening guidelines. Many of them are still recommending mammograms starting at age 40. And both the study mentioned above and the new American Cancer Society guidelines say choosing when and how often to get mammograms is a personal decision that each woman should make with her doctor. The American Cancer Society recommendations are influential, but doctors are NOT required to follow them. Talk to your doctor about what he or she thinks about the new guidelines.

For more information, read Living Beyond Breast Cancer's statement on these new guidelines.

Miglioretti, D., Zhu, W., Kerlikowske, K, et al. Breast Tumor Prognostic Characteristics and Biennial vs. Annual Mammography, Age, and Menopausal Status. Journal of the American Medical Association Oncology. Published online October 20, 2015; doi:10.1001/jamaoncol.2015.3084.

Oeffinger K., Fontham E., Etzioni R., et al. Breast Cancer Screening for Women at Average Risk: 2015 Guideline Update From the American Cancer Society. Journal of the American Medical Association. October 20, 2015; 314(15): 1599-1614; doi:10.1001/jama.2015.12783.