Mammogram Guidelines: FAQ

Medically Reviewed by Traci C. Johnson, MD on July 08, 2016
4 min read

If you're approaching the big 4-0, you're probably wondering if it's time to book your first mammogram -- or if you can put it off for another few years. It's no wonder you're confused: Conflicting guidelines from leading medical groups have made this issue murkier than ever. Some key facts can help you decide.

Q. When do health experts say you should start to get mammograms? 

The main expert you need to check with is your doctor. They will consider your particular case, including your age, family, and other things that make you likely to need mammograms sooner rather than later.

As for medical groups, there are many, and they don't agree on this issue.

For years, the American Cancer Society (ACS) urged women to start mammograms at 40, but they recently changed their guidelines. They now recommend beginning them at 45, or at 40 if the patient chooses.

Other groups, such as the American College of Obstetricians and Gynecologists (ACOG), say that starting at 40 is best. Meanwhile, the U.S. Preventive Services Task Force (USPSTF) says that women can wait until 50. 

There's also the related issue of how often to get tested. ACOG says go annually. USPSTF says every 2 years. The most recent ACS guidelines suggest getting annual mammograms between 45 and 54; after that, they say it's OK to wait 2 years between screening tests.

Q. So which group is right?

It's less a question of who's right and wrong and more about how various people interpret the data and which studies they pay most attention to. Experts in each of these groups have reviewed the evidence in favor of starting earlier vs. later and come to different conclusions.

"Nobody is arguing that fewer women won't die if they get mammograms at 40, and nobody is arguing there aren't harms that come along with starting that early," says Therese Bevers, MD, medical director of the Cancer Prevention Center at the University of Texas M.D. Anderson Cancer Center. She explains that groups pushing for later testing are simply giving more weight to the downsides.

Q. What kind of harm could there be?

“False-positives” and over-diagnosis are the biggest concerns. False-positives mean that a mammogram shows something suspicious that later turns out to be nothing. Those can happen at any age, but they're more common in younger women. Before menopause (which usually happens around age 50), women tend to have dense breasts, which can make mammograms harder to read. Getting called back for another mammogram or a biopsy can be stressful. In one survey, 40% of women who had this happen described it as "very scary" or "the scariest time of my life."

Earlier testing also means more cancers will be found. That sounds like a good thing -- you'd want to catch it, right? But some cancers grow so slowly that they're unlikely to make you sick or even shorten your life span. The problem is that doctors don't always know which ones will cause trouble and which won’t. So some women may get surgery, radiation, and chemotherapy that they don't really need because doctors want to be cautious.

Q. What are the upsides to starting mammograms at 40?

Simply put, you're less likely to die of breast cancer, says Bevers, who chairs the National Comprehensive Cancer Network's Breast Cancer Screening and Diagnosis Guideline Panel. That's why she, and many other doctors, still urge women to start at 40 and get checked annually.

Dennis Citrin, PhD, a cancer doctor at Cancer Treatment Centers of America at Midwestern Regional Medical Center, thinks that women should get their first mammogram at 40 to use as a comparison for future ones.

Q. How can I weigh the pros and cons?

Your doctor can help, but ask yourself these questions:

How would I feel if I got a false-positive? In one survey, more than one-third of women said they'd be willing to deal with more than 10,000 false-positive mammograms for every breast cancer death avoided.

How would I feel if I ended up with cancer treatment I didn't really need? One study found that as many as 10 women might be getting over-diagnosed for one death avoided.

Q. Should I be concerned about the radiation from mammograms?

Not really. The amount of radiation you get from one mammogram is equal to what you're exposed to while flying on an airplane from Houston to Paris and back, Bevers says. "It also takes 100 mammograms to equal the amount of radiation in one CT scan," she says.

Q. I have a family history of breast cancer. Do any of the guidelines we're talking about apply to me?

No. These guidelines are for women with an average risk of breast cancer. If you have a family history of the disease, a BRCA gene mutation, or other risk factors -- like being exposed to radiation as a child -- then you're at higher risk. Talk to your doctor for guidance on when and how often to get checked. You may even need to start before age 40, Citrin says.

The "rules" about when to get a mammogram also no longer apply if you find a lump in your breast, says Citrin, who's the author of Knowledge Is Power: What Every Woman Should Know About Breast Cancer. If you see or feel anything that’s not normal for you, then you need a mammogram ASAP to find out what it is. Many lumps are not breast cancer, but you can’t tell for sure by how it feels.

Q. No one in my family has ever had breast cancer. Why should I bother getting checked at any age?

Because if you have breasts, you can get breast cancer. "Eighty-five percent of all breast cancers are not related to a specific gene mutation," Citrin says. He adds that women who get regular mammograms are 20% less likely to die of breast cancer. "It may be uncomfortable, even painful, to do this every year or two, but it's worth it."