Learning About Adenoid Cystic Carcinoma (ACC) of the Breast

Adenoid cystic carcinoma (ACC) of the breast is a rare type of breast cancer. Less than 0.1% of all breast cancers are this type. This cancer begins in the milk glands of the breast, often under the nipple area. It can occur at any age in adults, but it is most often found in middle-aged and older adults.

ACC of the breast is less likely to spread to the lymph nodes or other parts of the body, and it grows slowly. It has a high survival rate, especially when found and treated early.

ACC of the breast may not cause symptoms at first. It may be found with a screening mammogram.

As the tumor grows, symptoms may include:

• A lump in the breast that feels firm or movable.
• Breast pain or soreness.
• Swelling or thickening in part of the breast.
• Redness of the skin.
• Nipple inversion (less common).

Because early breast cancer may not cause symptoms, it’s important to have screening mammograms. These can help detect breast cancer earlier, when treatment works better. Talk with your doctor about when to get screened.

Doctors use several tests to diagnose this type of cancer. They include:

• Mammogram. This is an X-ray of the breast. It can help show abnormal areas that may not be felt during a physical exam.
• Ultrasound. Breast ultrasound uses sound waves to create images of the breast tissue. It can help doctors learn more about an abnormal area seen on a mammogram or felt during an exam.
• Biopsy. A biopsy is needed to confirm a cancer diagnosis. During a biopsy, a small sample of tissue is removed. The tissue is examined under a microscope to see if it has cancer cells.

After diagnosis, tests may be done on the cancer cells. These tests help guide treatment choices. ACC of the breast is often triple-negative. This means the cancer cells do not have estrogen or progesterone receptors or high levels of HER2 protein. Many types of triple-negative breast cancer can grow fast, but ACC of the breast often grows more slowly. ACC of the breast tends to have a better outcome than other triple-negative breast cancers.

The types of treatment that your doctor advises will be based on these factors:

• The size of the tumor.
• How abnormal the cancer cells look (grade).
• How far they have spread (stage).
• What receptors they have.
• If there are cancer cells in the lymph nodes.
• Your overall health.

The treatment options can include:

• Surgery. This is usually the main treatment for ACC of the breast. Surgery options include:
  • Lumpectomy. This is done to remove the tumor and a small amount of surrounding tissue.
  • Mastectomy. This is done to remove all or most of the breast.
• Radiation therapy. This is often used after a lumpectomy to help destroy any remaining cancer cells. It can reduce the risk of the cancer returning.
• Chemotherapy (chemo). This is the use of medicines to kill cancer cells throughout the body. Many people with ACC of the breast may not need chemo. This is because this cancer often grows slowly. Your doctor will decide if chemo may help based on the tumor grade and stage and on lymph node status.
• Targeted therapy. This is not often used for ACC of the breast. It may be an option in some cases depending on the test results on the cancer cells.

Hormone therapy is not often used. This is because ACC of the breast often does not use estrogen or progesterone to grow.

A diagnosis of ACC of the breast can feel overwhelming. Support is available for both patients and caregivers.

Some options for getting support include:

• Breast cancer support groups.
• Counseling or therapy.
• Patient advocacy organizations.
• Talking with your care team so that they can connect you to services.