Many women experience a phone call from their breast imaging center. The call often concerns the patient coming back for additional imaging of tiny white spots called calcifications. Calcifications are frequently seen on mammograms — they occur most often in women over 50. They may appear in any woman's breasts and, occasionally, occur in a man's breast tissue.
Most breast calcifications are benign (non-cancerous). However, a few patterns of calcification are suggestive of some precancerous conditions or, even, breast cancer.
Why Do Breast Calcifications Form?
Calcifications are usually non-cancerous changes in the breast tissue associated with aging. But there are various causes for calcifications — your breast health provider will work to determine the cause of any breast calcification to ensure that the changes seen on a patient's mammogram are not cancerous.
Here are some of the causes of breast calcification.
- Blood vessel calcifications. Calcium build-up can occur in the breast's blood vessels just as it occurs in the heart, aorta, or leg blood vessels. This process is called atherosclerosis. A woman who has cardiovascular risk factors may experience calcifications.
- Breast cyst. A fluid-filled sac may occur in one or both breasts. Cysts are common and usually occur in women before the onset of menopause. Cysts also develop in postmenopausal women on hormone therapy. Cysts can be oval or round and usually feel like a grape or a balloon filled with water. Cysts usually have smooth, distinct edges. The area around a cyst may be tender. Sometimes, cysts become smaller after a women's period. Occasionally (less than 5% of the time), a cyst can contain specks of milk of calcium crystals or floating cholesterol crystals, which may appear as calcifications in a mammogram.
- Cell secretions. The glandular cells can produce calcium into the ducts.
- Ductal carcinoma in situ (DCIS). DCIS stands for ductal carcinoma in situ. DCIS means that cancer cells are located along the breast's milk duct's lining but have not spread. DCIS is called Stage 0 breast cancer. Higher-grade DCIS is more likely to result in breast calcifications. However, most calcifications are not cancerous.
- Fibroadenoma. Fibroadenomas occur most often in young women, ages 15 to 35. These breast growths are benign — they usually are hard (feel like a marble), with a well-defined shape, and usually aren't painful. They also move quite easily beneath the skin and may shrink or grow. Smaller fibroadenomas are often discovered on a woman's first mammogram. Larger fibroadenomas that occur in younger women may be biopsied.
- Infection. Women who breast-feed their babies may develop a breast infection called mastitis. Mastitis sometimes causes calcifications that are found on a woman's first mammogram. Women should tell their breast health providers about their history of mastitis.
- Injury to the breast. An injury to a woman's breast from a fall, auto accident, or skiing accident may result in calcifications to occur in the breast.
- Mammary duct ectasia. During the time just before menopause, a woman's milk ducts may enlarge. The walls of the ducts may become thicker. The duct may develop fluid that can thicken and block the duct.
- Previous radiation for breast cancer or previous breast surgery. Radiation therapy or surgery to the breast sometimes causes scarring to the breast tissue. This scar tissue may sometimes calcify.
What Do Breast Calcifications Mean?
Breast calcifications may not be significant, but experts agree that the radiologist reading your mammogram should study the images to determine if your calcifications indicate early breast cancer.
Calcifications appear as small white dots. If the radiologist sees these dots, he looks at them to determine several characteristics:
- Size – small or large.
- Shape – round, irregularly-shaped like popcorn, or rod-like.
- Pattern – randomly scattered or clustered.
Your doctor and the radiologist, based on their experience, determine if follow-up is necessary. The radiologist will compare your new mammogram to the previous one for comparison, if possible. Patients may be called back for a second mammogram, called a diagnostic mammogram. The second mammogram provides additional views of the suspicious areas. The radiologist then classifies the calcifications:
- Clearly benign
- Likely benign
- Suspicious or suggestive of cancer
Will I Need Follow-Up Tests?
Radiologists refer to the larger breast calcifications as macrocalcifications. Non-cancerous changes in the breast tissue usually cause these. No follow-up is needed, nor is any treatment required for breast calcifications that look normal.
Smaller breast calcifications, known as microcalcifications, may appear in patterns. If several calcifications look like a line or are clustered together as a small group, they are suggestive of cancer. These patients need additional testing.
For calcifications that look suspicious, patients need additional tests. Every patient is different, so not every patient has every additional test.
Additional testing of breast calcifications may include:
- Magnified mammogram to have a clearer picture of the calcification
- An ultrasound exam utilizes sound waves to get a clear image – this exam can distinguish between a fluid-filled cyst or a solid tumor
- An MRI (magnetic resonance imaging) – the MRI creates magnetic fields that create images of the breast – the test utilizes a specialized liquid (called contrast) and given through an IV to help identify a tumor
- A needle core biopsy – a mammogram or ultrasound is used to pinpoint the small area of calcification – local anesthesia numbs the area
While a biopsy is scary, most women agree that they want to know if they have cancer to get it treated as quickly as possible.
Do Calcifications Increase My Risk of Developing Breast Cancer?
Breast calcifications are common — about half of all women over 50 develop calcifications, and 10% of women under 50 show calcifications.
- Women who have had macrocalcifications (the larger calcifications) are not at increased risk for breast cancer. These larger calcifications are not associated with the development of breast cancer.
- Microcalcifications (the smaller type of calcifications) can sometimes put women at an increased risk of developing breast cancer. If microcalcifications occur in small lines or small clusters, a woman might be at increased risk of developing breast cancer. In these circumstances, the radiologist and her doctor recommend additional testing.
About 80% of microcalcifications are benign. If biopsy results show no cancer, these small areas will be compared annually to detect changes. An additional biopsy is only needed when a new area of microcalcifications is detected or there's a change from a patient's previous mammogram.
A study reviewed the records of almost 64,000 Dutch women. Mammography in the Netherlands is available to all women, ages 50 to 74, on an every-other-year basis. The study showed that about 16% of invasive cancers could have been detected before they became invasive if women had been recalled for additional imaging when calcifications were detected. Earlier detection would have also reduced the percentage of tumors over 20 mm in size.
Radiologists at breast cancer imaging centers don't want to cause unnecessary worry in patients. Still, they will err on the side of caution to ensure that early breast cancer is detected. Careful use of new digital technology and the knowledge of which types of calcifications are linked to an increased risk of breast cancer offer women increased assurance that their breast cancer will be detected when it's most treatable.