There are several different types of breast cancer, including:
- Infiltrating (invasive) ductal carcinoma. Starting in your milk ducts of your breast, this cancer breaks through the wall of your duct and spreads to surrounding breast tissue. Making up about 80% of all cases, this is the most common type of breast cancer.
- Ductal carcinoma in situ. Also called Stage 0 breast cancer, ductal carcinoma in situ is considered by some to be precancerous because the cells haven’t spread beyond your milk ducts. This condition is very treatable. However, prompt care is necessary to prevent the cancer from becoming invasive and spreading to other tissues.
- Infiltrating (invasive) lobular carcinoma. This cancer forms in the lobules of your breast (where breast milk production takes place) and has spread to surrounding breast tissue. It accounts for 10% to 15% of breast cancers.
- Lobular carcinoma in situ is a precancerous condition in which there are abnormal cells in the lobules of your breast. It isn’t a true cancer, but this marker can indicate the potential for breast cancer later on. So, it’s important for women with lobular carcinoma in situ to have regular clinical breast exams and mammograms.
- Triple negative breast cancer (TNBC). Making up about 15% of all cases, triple negative breast cancer is one of the most challenging breast cancers to treat. It’s called triple negative because it doesn’t have three of the markers associated with other types of breast cancer. This makes prognosis and treatment difficult.
- Inflammatory breast cancer. Rare and aggressive, this type of cancer resembles an infection. People with inflammatory breast cancer usually notice redness, swelling, pitting and dimpling of their breast skin. It’s caused by obstructive cancer cells in their skin’s lymph vessels.
- Paget’s disease of the breast. This cancer affects the skin of your nipple and areola (the skin around your nipple).
Cancers form in other parts of the breast
When we say “breast cancer,” we usually mean cancers that form in milk ducts or lobules. Cancers can also form in other parts of your breast, but these types of cancer are less common. These can include:
- Angiosarcoma. This rare type of cancer begins in the cells that make up the lining of blood or lymph vessels.
- Phyllodes tumors. Starting in the connective tissue, phyllodes tumors are rare. They’re usually benign (noncancerous), but they can be malignant (cancerous) in some cases.