In 2009, an influential panel updated its guidelines about mammograms -- when women should start getting them and how frequently -- and ignited a firestorm. More on their recommendations below, but in short, the U.S. Preventive Services Task Force said that average-risk women in their 40s could skip screening and start every-other-year mammograms at age 50.
Since then, the august American Cancer Society stayed its course and kept recommending that women get annual mammograms starting at age 40.
Until today. Now, in updated guidelines, the American Cancer Society says that women can wait to commence mammograms until age 45 and have them every year until age 54. Starting at 55, women should have them every other year.
The recommendation is for women at average risk, not for women with a family history or other factors that would put them at higher risk. The new guidelines were published in the journal JAMA.
These are "big changes" for the American Cancer Society, writes Liz Szabo at USA Today:
As recently as 1992, the American Cancer Society recommended women get a "baseline" mammogram at age 35 to 39, so that doctors would have an image to which to compare their later screening results.
The new guidelines reflect the growing recognition that mammograms can do harm, as well as good, said Richard Wender, chief cancer control officer at the American Cancer Society.
"The biggest evolution has been not in the American Cancer Society, but in the science of cancer screening and the evolution of health care in general," Wender said.
In another significant change, the cancer society also said doctors should no longer perform routine clinical breast exams. There's no evidence that these exams save lives.
While the cancer society's guidelines move closer to that of the task force that ignited a debate, the two organizations recommendations still differ:
- American Cancer Society -- ages 45-54 annual mammograms; age 55 and for as long as a woman is healthy -- and has a life expectancy of at least 10 years -- every other year
- U.S. Preventive Services Task Force -- mammograms every other year starting at age 50, until age 74. More research is needed, the group says, on potential benefits in women 75 and older
As the cancer society has moved toward less frequent screening, Rob Stein at NPR reports that some experts hope that it will reduce confusion in women:
"There really is not a single answer to the question: Should I have a mammogram?" says Nancy Keating, a professor of health care policy at Harvard Medical School and a physician at the Brigham & Women's Hospital.
"It really involves looking at each patient individually," she says, "thinking about their risk of developing breast cancer and thinking about the harms." She co-authored an editorial published with the new guidelines.
But it doesn't look like the new guidelines will end the debate. The American College of Radiology and the Society of Breast Imaging, for example, still recommend annual mammography beginning at age 40. Later, less frequent screening could be risky, they say.
"I am personally concerned as a woman and as a person heavily involved in breast cancer screening [that] there will be lives that we could save that will be lost," says Dr. Debra Monticciolo, a professor of radiology at Texas A&M Health Science Center College of Medicine. She chairs the radiology college's commission on breast imaging.
A 2011 study cited in the article explaining the new [cancer society] guidelines found that 61 percent of women who had yearly mammograms starting at age 40 had at least one false positive by the time they were 50. Being tested every other year instead of every year can cut the false positive rate significantly, ... to about 42 percent from 61 percent.
Some women consider false positives a small price to pay for the chance of identifying a cancer early. Others find being called back for more tests too nerve-racking.
Another potential risk of mammography is overdiagnosis, meaning that some of the tiny cancers it finds might never progress or threaten the patient’s life. But because there is now no way to be sure which will turn dangerous, they are treated anyway.
The treatment can include surgery, radiation and chemotherapy.
In a statement, the San Francisco-based Breast Cancer Action, which has long advocated for changes in screening guidelines, said it welcomed the "long overdue step" by the cancer society.
“After years of relentlessly promoting annual mammography for women age 40 and older and overstating the benefits of early detection, the ACS is finally starting to follow the evidence on the limitations of routine breast cancer screening for women at average risk,” said Karuna Jaggar, executive director of Breast Cancer Action.
"The reality is tens of thousands of women each year would have been spared the harms of overtreatment if the ACS and other large cancer organizations had followed the evidence sooner," Jaggar said.
The cancer society says women ages 40-44 who wish to have mammograms should be informed of the test's risks and benefits.
The U.S. Preventive Services Task Force is in the process of updating its guidelines, especially for women in their 40s, and now says: "The decision to start screening mammography in women prior to age 50 years should be an individual one."