Skip to main content

When it’s time to get a mammogram, which one do you need?

While you may know that you should start getting annual mammograms at age 40, you may not know the difference between screening and diagnostic mammograms. Knowing the difference can help avoid confusion.

What is a mammogram?

Before we dive into the different types of mammograms, it’s important to understand what a mammogram is and what it does. A mammogram is a low-dose X-ray exam that can spot any 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 or other abnormalities,” says  Dr. Anne Dunne, a diagnostic radiologist at Geisinger Medical Center in Danville.

The recommended age to begin yearly mammograms is 40; however, if you have a family history of breast cancer, talk to your doctor to see if starting screening earlier is right for you.

Now, let’s look at the difference between a screening mammogram and a diagnostic mammogram. 

Screening mammograms

Screening mammograms are performed yearly on women, typically aged 40 and above, to screen for signs of breast cancer. Screening mammograms are done on women who show no symptoms of breast cancer, such as a lump, skin changes, nipple discharge or a change since their last breast exam.

“The goal of a screening mammogram is to detect signs of breast cancer as early as possible, before there are any outward signs,” explains Dr. Dunne. “When breast cancer is found early on — when it’s small — it improves the chances of successful treatment.”

During a screening mammogram, a specially trained and certified technologist will take two images of each breast. Depending on breast size, a few additional images might be needed to include all the tissue. A diagnostic radiologist reviews the images for any abnormalities and sends a report to your doctor. 

You’ll receive a letter telling you one of two things: that your mammogram was normal or that something was seen and you will need further evaluation.

Diagnostic mammograms

If the doctor finds an abnormality on your screening mammogram, you’ll likely have another mammogram called a diagnostic mammogram. You may also have a diagnostic mammogram if you’re having symptoms such as a lump, skin changes or nipple discharge.

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

During a diagnostic mammogram, the technologists will take images as directed by the radiologist to evaluate the finding on your screening mammogram or the symptoms you’re having.  

“In some cases, a breast ultrasound must be done at that time as well to get a closer look at a certain area,” says Dr. Dunne.

You’ll get the results of your diagnostic mammogram during your visit. You may hear:

  • There is no cause for concern, and you can return to having regular screening mammograms.
  • It is most likely nothing to worry about, but you should have another mammogram within six months to make sure there are no changes.
  • It may be breast cancer and a biopsy is needed to know for sure.

Getting a yearly mammogram is a smart way to take charge of your breast health. The earlier doctors can catch any sign of cancer, the more effectively they can treat it. If you have any questions about your mammogram or your results, be sure to ask your doctor.

Next steps: 

Learn about breast health care at Geisinger 
Schedule an appointment with Anne Dunne, MD
Learn about our high-risk breast clinic