Also known as breast carcinoma, breast cancer starts in the cells of the breast tissue. These abnormal cells then begin to multiply out of control and form a lump or tumour.
Although gene mutations can be inherited from a parent, most cancers develop as a result of gene mutations that develop in the cells during a person's lifetime. Nobody knows the exact cause of breast cancer, but we do know that some people have a higher risk of developing it.
Cancer develops gradually as a result of a complex mix of risk factors related to:
- lifestyle (tobacco use, diet, exposure to sunlight)
- the environment
Cancer cells may start within the ducts (ductal carcinoma) or in the lobules (lobular carcinoma). Ductal carcinoma is the most common type of breast cancer.
Other types of breast cancer such as Inflammatory Breast Cancer and Paget’s Disease behave differently and may need different treatment.
Find out more from the Canadian Cancer Society