Mammography is a widely used screening tool for detecting breast cancer early, which can improve treatment outcomes. Many individuals experience anxiety when their mammogram results are not immediately clear. An “abnormal” result from a screening mammogram is common, prompting further investigation.
What an Abnormal Mammogram Means
An abnormal mammogram result means the radiologist identified something requiring additional evaluation. This finding does not automatically indicate cancer, but rather signals the need for a closer look. Each year, approximately 10% of women undergoing screening mammograms are asked to return for more tests. Most abnormal findings are not breast cancer, with only a small percentage of additional tests leading to a cancer diagnosis. Most reveal benign (non-cancerous) conditions.
Common reasons for an abnormal mammogram include dense breast tissue, which can obscure potential abnormalities. Benign findings like fluid-filled cysts, non-cancerous masses such as fibroadenomas, or calcium deposits (calcifications) can also appear and necessitate further investigation. Overlapping normal breast tissue can sometimes create a suspicious appearance, leading to a false positive result where an abnormality is indicated, but no actual issue exists.
Why Results Vary
Several factors influence the percentage of abnormal mammograms requiring follow-up. Breast density is a factor, as dense tissue (which appears white on a mammogram) can make it challenging to detect potential cancers, which also appear white. The American College of Radiology’s Breast Imaging Reporting and Data System (BI-RADS) categorizes breast density from A (almost entirely fatty) to D (extremely dense), with higher density often correlating with increased call-back rates.
A person’s age can affect call-back rates, with younger women and those undergoing their first mammogram often having a higher likelihood of recall due to a lack of previous images for comparison. Hormonal status, such as being pre-menopausal or on hormone replacement therapy, can influence breast tissue appearance and lead to more recalls. The expertise and volume of mammograms read by the radiologist can also play a role, as experienced radiologists or those reading a higher volume of exams may have lower recall rates.
What Happens After an Abnormal Finding
If a mammogram result is abnormal, the next step typically involves additional imaging tests to clarify the finding. This often begins with a diagnostic mammogram, capturing more detailed or magnified views of the area of concern. A breast ultrasound may also be performed, using sound waves to differentiate between fluid-filled cysts and solid masses. In some instances, a breast MRI might be recommended, providing detailed images using magnets and radio waves.
These follow-up tests aim to get a clearer picture and determine if the abnormality is benign or requires further investigation. If additional imaging still raises suspicion, a breast biopsy may be recommended. During a biopsy, a small tissue sample is removed from the suspicious area and examined under a microscope to check for cancer cells. Most biopsy results for abnormal mammogram findings turn out to be benign. Maintaining open communication with healthcare providers and attending all recommended follow-up appointments are crucial.