There are different types of breast cancer. Knowing the type of breast cancer you have helps your doctor to plan the best treatment for you.
Breast cancer can be non-invasive (also called in situ) or invasive.
Non-invasive breast cancer stays within the ducts or lobules and is called ductal carcinoma in situ (DCIS).
Invasive breast cancer is when the cancer cells spread outside the milk ducts or lobules where they first started. Most breast cancers are invasive and can be grouped as:
- no special type (NST)
- special types.
Other less common types of invasive breast cancer include:
- invasive lobular breast cancer
- inflammatory breast cancer
- Paget’s disease of the breast.
Some breast cancers are also identified by whether or not the cancer cells have receptors for hormones or a protein called HER2 (HER2 positive breast cancer).
Breast cancer that does not have receptors for HER2 or hormones is called triple negative breast cancer.
Some women have abnormal cell changes in the lining of the lobules. This is called lobular carcinoma in situ (LCIS). LCIS is not a cancer. It means a woman has a slightly increased risk of developing breast cancer in later life.
Invasive breast cancer means the cancer cells have spread outside the lining of the ducts or lobes and into the surrounding breast tissue. There are different types of invasive breast cancer.
No special type (NST)
This includes ductal invasive breast cancer, which is the most common type of breast cancer. About 7 to 8 out of 10 of all breast cancers (70% to 80%) are this type.
This is when the breast cancer cells are examined under the microscope and they have no specific features. They are called breast cancer of ‘no special type’ (NST) or ‘not otherwise specified’ (NOS).
Some breast cancer cells have features that identify them as a specific type of breast cancer. These are called special type breast cancers and are rare. They are named depending on how the cells look under a microscope and include tubular, medullary, mucinous, cribriform.
Other types of breast cancer
There are some other less common types of invasive breast cancer.
Invasive lobular breast cancer
About 1 in 10 invasive breast cancers (10%) start in the lobes of the breast. This type can sometimes be difficult to diagnose on a mammogram because of the way it grows. Some women may need an MRI scan.
Inflammatory breast cancer
This is when cancer cells grow along and block the tiny channels (lymph vessels) in the skin of the breast. The breast then becomes inflamed and swollen. Inflammatory breast cancer is rare.