Not ONE type: The Amoena guide to what “breast cancer” means

“Breast cancer” includes a lot of different types and stages. Our simple guide can help make sense of them.

The words “breast cancer” are used to describe a wide range of cancers found in the breast area. Here, we have prepared a simple guide to how these types are classified and other terms that you may hear related to your diagnosis.

Breast cancer is when cells in the breast area begin to change and divide abnormally. The type of breast cancer you have and the treatment you need for it depends on a lot of factors: where the cancer started, how big the tumor is, what kind of cancer cells are present and whether they have moved to other areas in the body.


Non-invasive breast cancer

Ductal carcinoma in situ (DCIS) is an early form of breast cancer in which some cancer cells have been found in the milk ducts, but they have not spread to the rest of the breast tissue. If it is not treated, there is a risk that it could become invasive. Therefore, treatment  with surgery, radiation and hormonal therapy (tamoxifen) is usually recommended. Nearly all women treated for this type of cancer are cured.

It is sometimes also known as pre-cancer or intraductal, non-invasive or pre-invasive cancer.


Lobular carcinoma in situ (LCIS) is not considered a breast cancer, despite its name. Here, some cells inside the breast lobules have started to change. Although it is associated with an increased risk, most women with LCIS don’t go on to develop breast cancer. Therefore, it is usually just managed with regular check-ups and mammograms.


Invasive breast cancer

Most breast cancers diagnosed are invasive breast cancer. This means that the cancer cells have spread from where they started and moved into the breast tissue. They can also potentially travel further to the lymph nodes and the rest of the body.


Invasive ductal breast cancer is the most common type of invasive breast cancer (80%). The cells began to change in the milk ducts of the breast.

You may also hear it referred to as no special type (NST) or not otherwise specified (NOS) breast cancer.


Invasive lobular breast cancer means that the cells first started to change in the lobes of the breast. It can develop at any age but is most commonly diagnosed in 45- to 55-year-old women. About 12% of invasive breast cancer diagnoses are of this type.


Less common types of breast cancer

Inflammatory breast cancer gets its name from how it looks – the skin on the breast appears red, inflamed and swollen. Cancer cells blocking the tiny lymph vessels in the skin cause this.


Paget’s disease of the breast usually appears as an eczema-type rash around the breast nipple. This may occur along with DCIS or invasive breast cancer.


Secondary/metastatic breast cancer

Secondary or metastatic breast cancer is the term used when the cancer cells have spread from the breast to other parts of the body, including the lungs, bones or brain. They usually travel through the bloodstream or the lymph nodes.


Other Factors

Before your doctors recommend the best treatment plan  for you, they will consider how big your tumor is, whether it has traveled to other parts of the body and how quickly it might grow. You may hear this referred to as staging and grading. They may also look at the types of receptors (proteins) in the cells.



The stage refers to the size of the tumor and whether it has spread beyond the breast area. It may be described using TMN staging or number staging.


TNM staging: Tumor, Node, Metastasis


Number staging



The grading is decided after looking at the cells in the laboratory and analyzing how quickly they are likely to grow.



Different cells contain different types of proteins, known as receptors.

HER2 (human epidermal growth factor receptor 2) is a gene that makes HER2 proteins. These are receptors on breast cells that normally help breast cells grow, divide and repair themselves. In some cases, the gene doesn’t work correctly, producing too many receptors and causing cells to divide abnormally. There are many different treatments available for HER2 positive cancer.


Hormone receptors

Female hormones such as estrogen and progesterone, which are naturally produced in the body, can stimulate the growth of breast cancer if the cells in the tumor contain these hormone receptors. This is known as hormone-dependent breast cancer. Depending on the hormone it is sensitive to, these tumors are also referred to as estrogen receptor positive breast cancer (ER+) and, less common, progesterone receptor positive breast cancer (PR+). They are usually treated with hormone therapy, which either blocks the effect of the hormones in the body, or stops the ovaries from producing them.


Triple negative breast cancer is the medical term used when none of these receptors are present.


BRCA1 or BRCA2 gene mutation

BRCA1 (BReast CAncer1) and BRCA2 (BReast CAncer2) are gene mutations that increase the risk of developing breast and ovarian cancer in women who inherit them. The treatment for breast cancer in women with BRCA mutation is essentially the same as for sporadic breast cancer except that it also takes the higher risk of developing cancer in the healthy breast and /or contracting ovarian cancer into consideration.