Breast Cancer: Understanding Mammogram Results

What if the radiologist sees something suspicious or abnormal on your mammogram? The fear of abnormal mammogram results is real, but facts may help calm it. Most abnormalities found in mammogram results are not breast cancer.

The American Cancer Society recommends having a baseline mammogram between ages 35 and 40, and then a screening mammogram every year after age 40. Questionable mammogram results sometimes require additional evaluation. With further examination (imaging studies and/or biopsy), most of these abnormalities are found to be normal breast tissue or benign (non-cancerous) tissue.

What Is a Screening Mammogram?

Screening mammograms are recommended annually for all women starting at age 40, even if they are asymptomatic, meaning that they have no signs or symptoms of breast disease.

In a screening mammogram, each breast is X-rayed in two different positions: from top to bottom and from side to side. When a mammogram image is viewed, breast tissue appears white and opaque and fatty tissue appears darker and translucent.

What If Something Looks Abnormal?

Potential abnormalities are found in 6% to 8% percent of women who have screening mammograms. This small group of women needs further evaluation that may include diagnostic mammography, breast ultrasound, or needle biopsy.

After the additional evaluation is complete, most of these women will be found to have nothing wrong.

What Is a Diagnostic Mammogram?

Diagnostic mammograms differ from screening mammograms in that the examination focuses specifically on an area of tissue that appeared abnormal in a screening mammogram. Diagnostic mammograms are also done for women who haven't had a screening mammogram but may be showing signs or symptoms of something abnormal in the breasts.

Depending on the potential abnormality, different studies may be done. In some women, only additional mammographic images are needed. In other women, additional mammographic images and an ultrasound are done.

How Does an Abnormality Appear on a Mammogram?

A potential abnormality on a mammogram may be called a nodule, mass, lump, density or distortion.

• A mass (lump) with a smooth, well-defined border is often benign. Ultrasound is needed to characterize the inside of a mass -- if the mass contains fluid, it is called a cyst.
• A mass (lump) that has an irregular border or a star-burst appearance (spiculated) may be cancerous and a biopsy is usually recommended.
• Microcalcifications (small deposits of calcium) are another type of abnormality. They can be classified as benign, suspicious or indeterminate. Depending on the appearance of the microcalcifications on the additional studies (magnification views), a biopsy may be recommended.

How Accurate Is Mammography?

Mammography is 85% to 90% accurate. Mammograms have improved the ability to detect breast abnormalities before they are large enough to be felt during a breast examination.

However, it is possible for a mass to be felt but not appear on a mammogram. Because of this, your healthcare provider should evaluate any abnormality that you feel when examining your breasts. A diagnostic mammogram or additional studies may be recommended.

Reviewed by the doctors at The Cleveland Clinic Taussig Cancer Center