There are many different types of breast cancer, and how they are classified depends on where the cancer develops and if it has spread. Noninvasive or In Situ cancers are still contained where they first developed and have not spread to other tissues in the body. Invasive breast cancers spread to surrounding breast tissue. When the breast cancer travels to other parts of the body, it is known as metastatic breast cancer.
Ductal Carcinoma In Situ (DCIS)
DCIS is a noninvasive cancer that is contained within the lining of the breast milk ducts and has not spread to any surrounding tissues. While it isn’t considered to be life-threatening, it can increase a person’s risk of developing an invasive breast cancer. Without treatment, DCIS can become an invasive breast cancer which can spread to other breast tissue, and potentially to lymph nodes and other organs in the body.
Lobular Carcinoma In Situ (LCIS)
LCIS is not considered to be a cancer. Cells contained in the lobules, which are the milk producing glands in the breast, look like cancer, but they don’t grow through the walls of the lobules. A person diagnosed with LCIS should be watched closely because their risk of having an invasive breast cancer later is much greater.
Invasive Ductal Carcinoma (IDC)
Like DCIS, this invasive breast cancer forms in the breast’s milk ducts, but it has spread beyond the duct walls into the surrounding breast tissue. Invasive ductal carcinoma, also called Infiltrating Ductal Carcinoma is the most common type of breast cancer. It can become metastatic, spreading to the lymph nodes and other areas in the body.
Invasive Lobular Carcinoma (ILC)
This invasive cancer starts in the milk-producing glands (lobules) and can be much harder to detect. Women who have this type of cancer can develop the disease in both breasts. While extremely rare, men can also be diagnosed with this disease.
Both Invasive Ductal Carcinoma and Invasive Lobular Carcinoma are the most common types of invasive breast cancer.
Less common types of cancer include:
Inflammatory Breast Cancer (IBC)
The symptoms for this type of cancer are different than other breast cancers. Inflammation including swelling and redness, not caused by an injury or infection may be present. IBC can also cause a thickening of the skin on the breast, creating the appearance of pitting; similar looking to the skin of an orange. These symptoms are caused by cancer cells that interfere or block the lymph vessels in the skin.
Paget Disease of the Nipple
This rare type of cancer starts in the breast ducts and spreads to the skin of the nipple and areola, the dark circle around the nipple.
Phyllodes tumors are rare breast tumors. These tumors develop in the connective tissue (stroma) of the breast. For the most part, the tumors are benign, but excisional biopsies are done to remove the entire tumor, which is the only way to be certain if it is benign, or malignant. Having this type of tumor does not increase a person’s risk for developing another type of breast cancer, but careful monitoring is necessary because tumors can reoccur after surgery.
Angiosarcoma is a cancer that starts in the cells of muscles, fat or the lining of blood or lymph vessels, and can affect both breast tissue and the skin of the breast, as well as other areas of the body. This may be caused by prior radiation exposure. It can look like a skin infection, a bruise, or a lesion that does not heal. The disease can spread so patients should be closely monitored after treatment.
Metastatic Breast Cancer
Breast cancer that has spread to lymph nodes and other parts of the body is called metastatic breast cancer, also called Stage IV. It is common for the cancer to spread to the bones, lungs or liver, but it can also spread to the brain or other organs in the body. Even though a breast cancer spreads to another organ, it's still considered to be breast cancer, as opposed to a new type of cancer.
Unlike other types of breast cancer, it is not dependent on hormones for growth and the cancer cells don’t over-produce the HER2 protein.
The name triple negative refers to breast cancer that is estrogen receptor negative (ER-), progesterone receptor–negative (PR-), and HER2 receptor-negative (HER2-). It is a more complex disease, and the medications used to block the estrogen and progesterone hormones and the HER2 protein are not as effective in treating it. There are however, a number of other chemotherapy drugs that are used, usually in combination with both surgery and radiation.
While anyone can be diagnosed with this type of cancer, it is typically seen in a younger population of women (under age 50). Both African American and Hispanic populations and people with a BRCA1 gene mutation are at a greater risk.
Triple negative breast cancer is more aggressive, more likely to spread and has a higher incidence of recurrence.