U-M experts clear confusion over mammography screening controversy

Sep 29 2010

A year after a government panel revised its recommendations for breast cancer screening, many professional organizations have not followed suit.

Where does this leave the average woman?

"Experts agree mammography saves lives, and all major organizations still recommend regular mammograms. The disagreement is in what age to start, what age to stop and how frequently you should have it done," says Mark Helvie, M.D., director of breast imaging at the University of Michigan Comprehensive Cancer Center.

Groups including the American Cancer Society, the National Comprehensive Cancer Network, the American Medical Association, the American College of Surgeons and the American College of Obstetricians and Gynecologists recommend yearly mammograms beginning at age 40.

The U.S. Preventive Services Task Force, however, changed its screening recommendations in fall 2009 to say women age 50-74 should be screened every two years, and average-risk women 40-49 should discuss screening with their provider.

The change in guidelines was based on a report that analyzed several randomized clinical trials and models of mammography screening. U-M experts point out that the recommendations are not consistent with the survival data, which show the lowest risk of dying from breast cancer came from screening annually beginning at age 40, although with more potential harms.

In recommending changes to mammography guidelines, the task force referenced potential harms of screening mammograms, which include anxiety, discomfort, radiation risk, the need for women to return for additional imaging and the risk of a biopsy being done when no cancer is present.

But studies show that mammography callbacks resulting in unnecessary biopsies are uncommon. Women screened annually will be called back for additional testing once every 12-16 years. And the average woman would need to be screened for at least 149 years before she would undergo an unnecessary biopsy.

"Some potential harms exist, but they should be viewed in context and compared to the harm of not screening. Most women who have routine screening mammography will not need a biopsy," says Mark Pearlman, M.D., vice chair and professor of obstetrics and gynecology at the U-M Medical School.

In addition, centers such as U-M will interpret screening results while a woman waits, if requested. This means women leave knowing the results of their mammogram, and if additional views are needed, they can be obtained right away.

U-M experts also warn that a change in guidelines could have the unintended consequences of magnifying disparities in breast cancer survival for African-American women, who are more likely to be diagnosed with the disease at a younger age.

"It would clearly be dangerous for adult women to completely discontinue or avoid mammograms because of the confusion created by the screening controversy. The U-M Breast Care Center follows the recommendations of the National Comprehensive Cancer Network for annual mammograms beginning at age 40, but we encourage women to discuss their individual risk of breast cancer with their physician in order to make a well-informed decision regarding the appropriate age to begin breast cancer screening," says Lisa Newman, M.D., M.P.H., director of the Breast Care Center at the U-M Comprehensive Cancer Center.

Newman adds that any lump or change in breast examination should be evaluated immediately, regardless of mammogram history.

Breast cancer statistics: 209,060 Americans will be diagnosed with breast cancer this year and 40,230 will die from the disease, according to the American Cancer Society