Types of mammograms

Screening mammograms

A screening mammogram is an x-ray exam of the breasts in a woman who has no symptoms. The goal of a screening mammogram is to find cancer when it is too small to be felt by a woman or her doctor. Finding small breast cancers early with a screening mammogram greatly improves a woman’s chance for successful treatment.

A screening mammogram usually takes 2 x-ray pictures (views) of each breast. Some patients, such as those with large breasts, may need to have more pictures to see as much breast tissue as possible.

Diagnostic mammograms

A diagnostic mammogram is an x-ray exam of the breast in a woman who either has a breast problem (for instance, a breast lump or nipple discharge) or has had a change show up on her screening mammogram.

During a diagnostic mammogram, more pictures are taken to carefully study the area of concern. In most cases, special pictures are enlarged to make a small area of suspicious breast tissue bigger and easier to evaluate. Many other types of x-ray pictures can be done, depending on the type of problem and where it is in the breast. For example, a diagnostic mammogram may offer a closer look and show that an area that looked abnormal is actually normal. When this happens, the woman goes back to routine yearly screening.

A diagnostic mammogram could also show that an area of abnormal tissue probably is not cancer, but the radiologist may not be ready to say that the area is normal based on these pictures alone. When this happens it is common to ask the woman to return to be re-checked, usually in 4 to 6 months.

Finally, the results of the diagnostic work-up may suggest that a biopsy is needed to tell whether the abnormal area is cancer. If your doctor recommends a biopsy, it does not mean that you have cancer. About 80% of all breast changes that are biopsied are found to be benign (not cancer). If a biopsy is needed, you should discuss the different types of biopsy with your doctor to decide which type is best for you. (See the “Imaging-guided breast biopsy” section to learn more about types of biopsy.)