Published on Jan 15, 2019
Authored by Pfizer Medical Team
Breast cancer is the most commonly diagnosed cancer in females in Australia, and the third most common cancer in New Zealand. Although many women are affected by breast cancer, many people may have questions about it. Read on to learn the facts.
Breast cancer is caused by the uncontrolled growth of cells in the breast. These cells can form a mass called a tumour. Although breast cancers can start in different parts of the breast, most begin in the glands that produce milk (called lobules) or in the tubes (called ducts) that bring milk to the nipple (see Figure 1).
Figure. 1. Diagram of the female breast
There are many different types of breast cancer. The most common types are carcinomas, which are named based on where they form and how far they have spread. The most common types of breast cancer are called ductal carcinoma in situ, invasive ductal carcinoma, and invasive lobular carcinoma. In situ is a noninvasive condition in which abnormal cells are found in the tissue where they began growing and have not invaded other tissue layers. Invasive means that the cancer has spread to other tissue in the breast.
There are two types of in situ cancers:
There are many different kinds of invasive breast cancer, but the two most common are:
Less common types of breast cancer include inflammatory breast cancer, Paget disease of the nipple, Phyllodes tumour, and angiosarcoma.
While most breast cancers occur in women, men can also develop it.
Most women who develop breast cancer have no clear risk factors for the disease and no family history of it. And having one or more risk factors does not mean that a woman will develop breast cancer. There are, however, certain risk factors that can increase a woman’s risk of developing breast cancer. These include:
Research has shown that most breast cancers are caused by damage to genes that happens by chance after a person is born. Only 5% to 10% of breast cancers are inherited (when gene changes—called mutations—are passed from one generation of a family to the next).
Women who inherit genetic mutations to certain genes have a higher risk of developing breast cancer. Chief among these are genes called BRCA1 and BRCA2.
While all women have BRCA1 and BRCA2 genes, mutations to these are rare Not every woman with a mutation will get breast cancer, but it does put her at increased risk. Breast cancers linked to the BRCA1 or BRCA2 mutations are often found in younger women and more often in both breasts. Mutations in the BRCA1 and BRCA2 genes also increase a woman’s risk of developing ovarian cancer.
In addition to mutations in the BRCA1 and BRCA2 genes, there are a number of other, less-common genetic mutations that can also increase a woman’s risk of developing breast cancer—though not as much as BRCA1 and BRCA2 mutations. These include ATM, TP53, CHEK2, PTEN, CDH1, STK11, and PALB2 genes.
Genetic testing can identify some women with inherited mutations in their BRCA1 and BRCA2 genes, as well as in certain other genes and biological markers. This information can help them work with their cancer specialist known as an oncologist to:
Read Next: How is Breast Cancer Diagnosed
Last reviewed: 17/03/2020
-Breast Cancer Network Australia
-Breast Cancer Foundation NZ
-Calculate your risk of breast cancer with the iPrevent tool from Peter Mac
-Health Direct: Breast Cancer
-McGrath Foundation: Find a nearest McGrath breast care nurse (Australia)