What are the different types of breast cancer?
Breast cancer can be of different types and sub-types, classified according to causes, aggressiveness and possible response to treatment. It is important to know the exact type of breast cancer in order for the treatment to be streamlined towards the best possible outcome.
Breast cancer can originate in different parts of the breast area, such as the ducts, the lobules, the connecting tissue between breasts, and in some cases, in the armpit area, where lymph nodes are located.
The treatment for different types of breast cancer usually depends on the site of primary origin, the state of invasion (spread) and the dependency of tumor growth on hormones such as estrogen or progesterone.
Reference guide to understand the different types of breast cancer
- Most breast cancers are carcinomas (carcinomas are cancers that start in the cells lining the organs or tissues)
- In-situ breast cancers are those that have not spread to the surrounding tissue, which makes them more treatable
- Invasive breast cancers are those that have an invaded basement membrane of epithelial lining in the ducts
- Metastatic breast cancers are those that have spread to other organs or parts of the body, such as the lungs, bones, liver, or brain
- Recurrent breast cancer refers to the return/relapse of breast cancer after a disease-free period in completely treated patient
Types of breast cancer
Ductal carcinoma in-situ (DCIS)
This is a highly treatable form of pre-cancer (sometimes called ‘stage 0’ breast cancer). It starts in a milk duct and is the most common type of non-invasive breast cancer. In DCIS, the cells are abnormal but have not spread to the surrounding tissue areas. If left untreated over time, or if mistreated, DCIS may progress and evolve into an invasive form of breast cancer.
Invasive ductal carcinoma (IDC)
This is the most common type of breast cancer. It accounts for up to 80% of all invasive breast cancer cases and is also known as ‘infiltrating ductal carcinoma’. Like DCIS, IDC also starts in a milk duct. It then breaks through the duct wall, and invades the surrounding breast tissue area as well as has the potential to spread to other parts of the body as well.
Invasive lobular carcinoma (ILC)
This type of breast cancer begins in lobules, or the milk-producing glands present in breasts. It is also known as ‘infiltrating lobular carcinoma’. ILC has the potential to spread beyond the lobules, into the surrounding breast tissue and it can also metastasize to other parts of the body. It accounts for nearly 10% of all invasive forms of breast cancer.
Inflammatory breast cancer (IBC)
IBC is a rare and aggressive type of breast cancer. It causes redness and swelling in one or both breasts. The affected breast starts to feel warm, heavy, and tender. For IBC patients, the skin around the breast area becomes hard and ridged. It does not show up easily in a screening mammogram, and compared to other types of breast cancer, IBC tends to strike five years earlier.
Paget disease of the breast (or the nipple)
Paget disease is another rare type of cancer that affects the skin of the nipple and the areola (the darker circle of skin surrounding the nipples).
It should be differentiated from eczema of the nipple. For people affected with Paget disease, the nipple and areola often become scaly, red, or itchy. Patients may also experience yellow or bloody discharge from the nipples. Most people with Paget disease are likely to have invasive breast cancer or DCIS in the same breast.
Metaplastic breast cancer
Metaplastic breast cancer is also an extremely rare and invasive type of breast cancer. It begins in a milk duct, and proceeds to form very large tumors. It can contain a combination of cells that are different in appearance as compared to typical breast cancers, and it is generally harder to diagnose.
Angiosarcoma of the breast
Angiosarcoma is a rare soft tissue tumor of the breast. It occurs in both a primary form without a known precursor, and a secondary form that has been associated with a history of breast tissue that has been previously exposed to radiation.