Know Before You Go: Mammogram

A mammogram can save your life. Know how to prep for your appointment, plus what to expect the day of.

Medically reviewed in April 2021

A mammogram is a type of x-ray used to detect changes in breast tissue, including those from early-stage breast cancer. It can reveal cancer up to one-and-half to four years before it’s noticeable on a physical exam.

“Screening mammography in the United States reduces the risk of dying from breast cancer by 30 to 40 percent because it shows subtle, early changes you might not be able to feel yourself,” says Dianne Johnson, MD, a breast radiologist at the Memorial Hospital Breast Center in Jacksonville, Florida.

Mammogram controversy: Should you get screened?
A 2017 study, which involved the records of over 95,000 Danish women between 1980 and 2010 has sparked debate over the pros and cons of catching breast cancer so early—when it might not always be appropriate to treat.

The study, published in the Annals of Internal Medicine, revealed up to one third of women diagnosed using screening mammograms were treated for cancer that never would have become life threatening. Potentially, the women could have “watched and waited” to see if the cancer grew, or gone without treatment all together. Researchers found that screening didn’t help to reduce the number of advanced cancers, either.

It’s important to recognize that not every positive mammogram means a breast cancer diagnosis, and not every breast cancer diagnosis means you need aggressive treatment.

After a new diagnosis, people should ask their doctor:

  • If genetic tests are available to determine if their cancer is aggressive
  • Whether early-stage cancers really require surgery or chemotherapy
  • If watching and waiting is an option

When should you go for a mammogram?
There are different screening recommendations based on your age and risk. Here is what the American Cancer Society recommends:

  • Starting at age 40: Women at an average risk for breast cancer should discuss the option of annual mammograms with their doctor.
  • Ages 45 to 54: All women should go for annual mammograms.
  • Ages 55 and older: All women should get a mammogram every two years. Some women may want to get screened annually if they’re at higher risk.

If you have no new symptoms or pain, but you fall into one of these age brackets, you’ll undergo a “screening mammogram.” A screening mammogram involves taking two routine X-ray images of each breast. This approach gives your radiologist a general view of each side.

“If there’s any kind of problem: pain, a lump, nipple changes, skin changes, nipple discharge, it’s no longer a screening mammogram,” says Johnson. At that point, you’ll require a diagnostic mammogram, which may involve additional images that focus in on specific areas of concern.

How to prepare for a mammogram
Try to have your mammogram done at the same facility every time so the radiologist can compare your results against old images. This will decrease the likelihood of being called back for unnecessary follow up and increase the odds of successful cancer detection.

Why? Holding X-ray views side-by-side allows your radiologist to see if you’ve had the same, unchanging spot for ages, or if you have a new area of concern. If you’re going to a different facility, bring along your old mammogram images, Johnson recommends.

Some other things to consider when preparing:

  • Avoid booking for the week before your period, when your breasts are most tender. “But if there’s a problem like a lump, just come right in. Don’t waste any time,” says Johnson. Breast changes from menstruation may affect your comfort level, but won’t interfere with testing.
  • Get screened at a dedicated breast center. That way, a radiologist who specializes in breast imaging will be the one interpreting your results.
  • Don’t wear deodorant, creams or powders under your arms on the day of testing. They can show up as white spots that look like calcifications, or mineral deposits that may or may not be caused by cancer. If your radiologist can’t tell the difference, you’ll be called back for more testing.

What to expect when you arrive
When you arrive, a technologist will offer you a gown to change into and ask you to undress from the waist up. Let them know about any concerning or painful spots, if you carry the BRCA gene mutation, and about any important medical history, such as surgeries, implants or a history of breast cancer.

The technologist will position your breasts, one at a time, on the mammogram machine. It will then compress your breasts between two plates to take your X-rays. The compression spreads breast tissue apart so a clear picture can be obtained with minimal radiation. It also holds your breasts still to prevent movement from ruining the images.

The pressure may be a little uncomfortable, but as soon as the X-ray is taken, the machine will automatically release. The more compression you can tolerate, the better the image, says Johnson.

When to expect your results
The whole procedure takes about 20 minutes. If you have implants or are undergoing a diagnostic mammogram, it can take longer because additional images are necessary.

For a typical screening mammogram, you should receive your results at a later date by mail or phone. If you don’t hear anything within 10 days, call your OBGYN or the facility. For a diagnostic mammogram, the radiologist will typically read your X-rays the same day.

Don’t let fear keep you from going for a mammogram
If your doctor asks you to go for a diagnostic mammogram, or if you’re called back after a screening, it doesn’t necessarily mean you have cancer. It’s common to be asked to return. “Only a small fraction of the people that are recalled need a biopsy and, of those biopsies, 75 percent are benign,” says Johnson.

Don’t let anxiety keep you home. Early detection can save your life.

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