Types of breast cancer
Breast cancer - types and subtypes
Breast cancer is not one disease. There are different types and subtypes of disease that are referred to as breast cancer. The treatment you receive for your breast cancer may be quite different from the other treatment other people you meet have.
Types of breast cancer
Non-invasive breast cancers
- Ductal carcinoma in situ (DCIS)
- Lobular carcinoma in situ (LCIS)
Invasive breast cancers
The most common types of breast cancers are:
- Invasive ductal carcinoma
- Invasive lobular carcinoma
Less common types of invasive breast cancer are:
- Locally advanced breast cancer
- Metastatic breast cancer
Subtypes of breast cancer
The subtypes of breast cancer are based on the genes a cancer expresses.
The three main subtypes are:
- Hormone receptor positive breast cancer
- HER2-positive breast cancer
- Triple negative breast cancer.
Types of breast cancer
Non-invasive breast cancers
Non-invasive breast cancers are cancers that are contained within the milk ducts or lobules in the breast. They have not grown into, or invaded, the normal breast tissue. Non-invasive cancers are called carcinoma in situ and are sometimes referred to as pre-cancers.
Ductal carcinoma in situ
Ductal carcinoma in situ (DCIS) is the most common type of non-invasive breast cancer. It starts in the milk ducts of the breast and is non-invasive because it hasn't spread into any surrounding breast tissue. DCIS isn't life-threatening but having DCIS can increase the risk of developing an invasive breast cancer later in life. Read more about DCIS.
Lobular carcinoma in situ
Lobular carcinoma in situ (LCIS) is non-invasive breast cancer that grows in the lobules (the milk-producing glands at the end of breast ducts). It is non-invasive as it has not spread into any surrounding breast tissue. LCIS isn't life-threatening but having LCIS can increase the risk of developing invasive breast cancer later on in life.
Invasive breast cancers
Invasive breast cancers have spread outside the ducts or lobules of the breast into surrounding breast tissue. ‘Early breast cancer’ is the term that refers to cancer that is contained within the breast and may have spread to surrounding lymph nodes in the breast or armpit (axilla) but not anywhere else in the body.
Invasive ductal carcinoma
Invasive ductal carcinoma (IDC) is the most common type of breast cancer. About 80% of all breast cancers are invasive ductal carcinomas. Invasive ductal carcinoma means that the cancer that began in the milk ducts of the breast has broken through the lining of the milk duct and spread into the surrounding breast tissue. Over time invasive ductal breast cancer can spread to the lymph nodes and potentially to other parts of the body.
Invasive lobular carcinoma
Invasive lobular carcinoma (ILC) is the second most common type of breast cancer after invasive ductal carcinoma. Invasive lobular carcinoma means that the cancer that began in the milk-producing lobules of the breast has broken through the lining of the lobule and spread into surrounding breast tissue. Over time invasive lobular breast cancer can spread to the lymph nodes and potentially to other parts of the body.
The US breastcancer.org website also has a range of very clearly explained information about invasive lobular breast cancer. This is an American website and please keep in mind not all information may be relevant to Australia.
Less common types of invasive breast cancer
Paget’s disease of the nipple
Paget's disease of the nipple is a rare form of breast cancer in which cancer cells grow in the nipple or the areola (the area around the nipple). The nipple and areola often become scaly, red, itchy, and irritated. Many people with Paget’s disease may also have either DCIS or invasive breast cancer somewhere else in the breast. The unusual changes in the nipple and areola are often the first signs that breast cancer is present.
Inflammatory breast cancer
Inflammatory breast cancer is a rare and aggressive form of invasive breast cancer that affects the blood vessels in the skin and/or lymphatic vessels of the breast. This causes the breast to become red and inflamed. See Cancer Australia for more information about inflammatory breast cancer.
Phyllodes tumours of the breast
Phyllodes tumours of the breast are rare. Although most phyllodes tumours are benign (not cancerous) some are malignant (cancerous). Phyllodes tumours tend to grow quickly, but they rarely spread outside the breast. Phyllodes tumours develop in the breast’s connective tissue or stroma (the tissue that holds everything together inside the breast) i.e. outside the ducts and lobules of the breast.
Other rare breast cancers
There are also other types of very rare breast cancers such as metaplastic, medullary and mucinous breast cancer.
The US breastcancer.org website has a range of very clearly explained information about the rarer types of breast cancer. This is an American website and please keep in mind not all information may be relevant to Australia.
Locally advanced breast cancer
Locally advanced breast cancer is an invasive breast cancer that is 5cm or larger or has spread beyond the breast to other nearby areas such as the skin, chest wall or muscle and may have extensive local lymph node involvement. Read more about locally advanced breast cancer
Metastatic breast cancer
Metastatic breast cancer, also known as advanced, secondary or stage 4 breast cancer, is breast cancer that has spread to more distant parts of the body such as the bones, liver, lungs, or brain although it has the potential to spread anywhere in the body Read more about metastatic breast cancer
Subtypes of breast cancer
The three main subtypes of breast cancer.
Hormone receptor positive breast cancer
About two-thirds of breast cancers are hormone receptor positive, which means that they need female hormones (oestrogen and/or progesterone) to grow and reproduce. Most people with hormone positive breast cancer will be recommended hormone-blocking therapy such as tamoxifen, anastrozole or letrozole. These are oral medications that are taken daily for at least five years following the completion of other breast cancer treatments (surgery, chemotherapy and/or radiotherapy).
HER2-positive breast cancer
HER2-positive breast cancer cells have too much of the protein called human epidermal growth factor receptor 2 on the surface of the cancer cells compared with normal cells. These excess HER2 receptors promote the growth of the cancer cells. HER2-positive breast cancer may be either hormone receptor positive or negative. Around 20% of breast cancers are HER2 positive.
There are a number of effective targeted therapies to treat HER2 positive breast cancers. The targeted therapies are designed to target specific characteristics of the cancer cells such as the HER2 protein, stopping the cancer cells from dividing and growing. The drug trastuzumab is the most commonly used targeted therapy for HER2-positive breast cancer. Most people with HER2-positive breast cancer will have targeted therapies along with other treatments including surgery, chemotherapy and/or radiotherapy. They may also be recommended hormone-blocking therapy if the cancer is also hormone receptor positive.
Triple negative breast cancer
Triple negative breast cancer does not have any of the three receptors commonly found on breast cancer cells (oestrogen, progesterone and HER2). Around 15 per cent of breast cancers are triple negative and chemotherapy is generally recommended for these cancers. Targeted therapies and the role of immunotherapies are being actively studied in the treatment of triple negative breast cancers. Immunotherapy medicines work by helping the immune system work harder and better to fight cancer cells. Read more about triple negative breast cancer.
More Information
- For more information on breast cancer types and subtypes Visit My Journey
- Cancer Australia also provides information about the different types of breast cancer.
BCNA’s My Journey
My Journey is where you go to get all your breast cancer information about your diagnosis in one place. Whether you have early breast cancer, DCIS or metastatic breast cancer, My Journey provides you with the latest information tailored to suit your situation. You can access this information through My Journey via an app or web browser at www.myjourney.org.au