Screening vs. Diagnostic Mammogram

When it’s time for a breast cancer screening, which one do you need?

Early detection is the most effective weapon against breast cancer. It’s a fact that regular mammograms save thousands of lives every year — and could save yours, too.

A mammogram is a low-dose X-ray exam that can spot many abnormal changes in your breast tissue that can’t be felt during a breast exam.

“Mammograms help detect and diagnose breast cancer and benign (non-cancerous) conditions of the breast that could be causing a lump, skin changes, nipple drainage or other abnormalities,” says Ebonee Carter, MD, a diagnostic radiologist at Geisinger. “And when breast cancer is caught in its earliest, localized stage, the 5-year survival rate approaches 99%.”

While you may already know that you should start getting annual mammograms at age 40 — or earlier if you have risk factors — you may not know there are 2 types of mammograms: screening and diagnostic mammogram. They both use the same specialized X-ray machine, but the appointments are very different. Learn the difference so you can take proactive steps toward maintaining optimal breast health.

What’s a screening mammogram?

Screening mammograms are performed yearly to check for signs of breast cancer. Screening mammograms are done on women who have no breast complaints and show no breast cancer symptoms, such as a lump, skin dimpling, nipple discharge or a change in size or shape since their last breast exam.

“The goal of a screening mammogram is to detect breast cancer as early as possible, before there are any outward signs,” says Dr. Carter. “Some types of breast cancer can grow and spread without physical signs showing up during a clinical breast exam. So when breast cancer is found early on — before it progresses locally or distant — it significantly improves the chances of successful treatment.”

During a screening mammogram, a specially trained and certified technologist positions your breast between 2 plates that compress the tissue evenly to acquire clear images. Typically, 2 images of each breast are taken from different angles, but depending on breast size, a few additional images might be needed to include all the tissue. The exam usually takes between 15 and 20 minutes.

Then, a diagnostic radiologist reviews the images for any abnormalities and sends a report to your doctor. In about a week, you’ll receive a letter telling you that your mammogram was normal and you should continue with annual screenings or that something was detected and you’ll need further evaluation.

What’s a diagnostic mammogram?

A diagnostic mammogram is used to help diagnose the source of symptoms or reasons for an abnormal finding on a screening mammogram.

“A diagnostic mammogram is also done for women who have previously been treated for breast cancer, especially during the first 3 to 5 years after treatment,” says Dr. Carter.

During a diagnostic mammogram, the technologist takes images as directed by the radiologist to evaluate the finding on your screening mammogram or the symptoms you’re having. It’s a more in-depth evaluation that includes additional views of a specific area and sometimes advanced imaging.

“In some cases, a breast ultrasound will also be done at that time to get a closer look at a certain area,” says Dr. Carter.

Diagnostic mammograms can take longer because they’re more comprehensive, but you can expect to get your results during your visit. You may hear:

There’s no cause for concern, and you can return to having regular screening mammograms.
It’s most likely nothing to worry about, but you should have another mammogram and possibly breast ultrasound within 6 months to make sure there are no changes.
It could be a sign of breast cancer and a biopsy is needed to know for sure.

“If you’re called in for a diagnostic mammogram, know that it doesn’t always mean cancer,” says Dr. Carter. “It just means we want to look at an area more closely. And in most cases, your results will come back negative for breast cancer.

Importance of breast cancer screening and early detection

The recommended age to begin yearly mammograms is 40. However, if you have a family history, genetic predisposition or other risk factors of breast cancer, talk to your doctor to determine if earlier breast cancer screening is right for you.

In addition to regular clinical breast exams, getting a yearly mammogram is the best way to take charge of your breast health.

“If you notice any changes in your breasts or develop symptoms, talk to your doctor right away — even if you recently had a normal screening mammogram,” says Dr. Carter. “The earlier doctors can catch any sign of cancer, the more effectively they can treat it — sometimes with less invasive options.”