November 19, 2009
New mammography screening guidelines
In a departure from past recommendations on breast cancer screening, new expert advice says that most women should not start mammograms before age 50, and it's best for the tests to come every two years. These new recommendations come from the U.S. Preventive Services Task Force. This is the most influential group that provides preventive care guidelines for doctors. The new guidelines are the first that this group has issued on breast cancer screening since 2002.
Women ages 40 to 49 are the ones most affected by this new advice. Some women in this age group already get mammograms. Based on the new recommendations, these women would stop these yearly tests until age 50.
For more than five years, the American Cancer Society and the National Cancer Institute have endorsed a mammogram every one to two years for women ages 40 to 49. They have the same advice for women 50 and older. But the American College of Physicians issued a different guideline two years ago. It said mammograms should be optional for women ages 40 to 49. It advised women to talk to their doctors about the pros and cons of screening.
Limited benefit for women in their 40s
Now the U.S. Preventive Services Task Force has concluded that screening women in their 40s offers limited benefits and may do more harm than good. This opinion is based on a thorough review of the latest research.
Many women have an emotional reaction to breast cancer, made all the more understandable because they have family or friends whose lives were up-ended by breast cancer.
About one out of every eight women will get breast cancer during a lifetime. When breast cancer is found early, as mammograms can allow, it is usually curable. Some women under 50 do get breast cancer. So why wouldn't early mammograms be a good idea?
By one estimate, in order to save six women from dying of cancer, about 10,000 women in their 40s need to get mammograms every one to two years. So what’s the problem? Mammograms are harder to read in young women. For this reason, almost half of women under age 50 who have mammograms are called back for repeat films or biopsies because their test results look suspicious. Most often, these areas of concern turn out to be "false positive," that is, not cancer. While that is good news, it is important to remember that additional tests and procedures are needed to determine for certain whether these suspicious results are cancer or not. Those tests and procedures carry their own risks and for some women, these include what will prove to be unnecessary risk from biopsy procedures.
What changes can I make now?
Most primary care doctors will probably work by the task-force guidelines. The task force did not find a big difference in benefit between having mammograms done every year and every two years. This is why the group strongly recommends a two-year wait between tests.
The benefit of office exams by your doctor to feel for breast lumps is hard to calculate. It may not be an important part of our breast-cancer screening plan.
Here are the task-force recommendations, by age group:
- Most women under age 50 don't need mammograms. Women who are at high risk for breast cancer are a special case. They should discuss a screening schedule with their doctor. Women who are at highest risk for breast cancer include those who have:
- Two first- or second-degree relatives who developed breast cancer before the age of 50
- Three first- or second-degree relatives who got breast cancer at any age
- A known gene mutation that is linked with breast cancer.
A first-degree relative is a mother, daughter, or sister. Second-degree relatives include aunts and grandmothers.
- Women aged 50 to 74 should get a mammogram every two years. The task force did not find enough information to make a strong statement about more tests — such as MRI — for women at high risk.
- For women over 74, there is not enough evidence to recommend for or against having mammograms. Although mammograms do detect more early cancers, overall survival is not improved by screening mammography.