CancerQuest | Results of a Mammography

The radiologist who reads the mammograms has a difficult job because the normal appearance of the breasts is different for each woman. For this reason, it is valuable to have previous mammograms available for comparison. Therefore, if mammographies are scheduled at different locations, the patient should make sure that the new facility has access to any previous mammograms. Mammography does not directly detect cancer. Instead, it is used to detect possible abnormalities, which can then be checked by a biopsy to determine if the changes are cancerous or benign. Depending on the radiologists' interpretation of an abnormality, the patient may be asked back for more diagnostic mammograms, for a follow up mammogram in 3-6 months, ultrasound, and/or biopsy. A common finding on mammogram is a cyst (a benign collection of fluid in the breast). The way to determine if a detected abnormality is a cyst is through an ultrasound examination or by needle aspiration.⁽¹⁾

On the mammogram, there are two principal signs of cancer: calcifications and/or the presence of a mass. Calcifications (deposits iof calcium compounds in the breast) show up as white spots on a mammogram and occur in two forms, microcalcifications and macrocalcifications. Macrocalcifications tend to be large and coarse looking and are associated with aging. They are common in women over 50, and are present in a small percentage of younger women. Macrocalcifications are not typically associated with cancer. Microcalcifications are smaller and are considered a sign of possible malignancy, even without a visible mass. The radiologist must interpret the characteristics of the mass to determine the possibility of cancer, and will order diagnostic tests and possibly a biopsy.⁽¹⁾

The image on the left shows the mammogram of a normal breast, while the image on the right shows a mammogram with an abnormality detected (denoted by the red arrows). Click on the images to visit their source, the Breast Center of St. Louis University.

Requests for additional testing does not necessarily mean there is anything to fear. The clincians may call a patient back just because something looks a little suspicious and they would like to make a more thorough examination. In the event that a biopsy is indicated the likelihood of cancer is still small. Only 8-10% of those called back will need a biopsy, and approximately 20% of those will be diaganosed as having some form of cancer.⁽¹⁾

Women with denser breasts show a decreased mammographic sensitivity, meaning it is harder to interpret the x-rays films and to see all of the breast tissue clearly. Ultrasound has been considered as an alternative to or supplementary to mammography for women with dense breasts because it can more effectively screen all of the breast tissue.⁽²⁾ However, ultrasound is not effective in detecting microcalcifications, which are an early sign of possible breast cancer. ⁽¹⁾