Breast cancer is the most common cancer in the UK. About 48,000 women get breast cancer in Britain each year. Most (8 out of 10) are over 50, but younger women, and in rare cases, men, can also get breast cancer.
A woman's breasts are made up of fat, connective tissue and thousands of tiny glands, known as lobules, which produce milk. If a woman has a baby, the milk is delivered to the nipple through tiny tubes called ducts, which allow her to breastfeed.
Our bodies are made up of billions of tiny cells. Normally, cells grow and multiply in an orderly way. New cells are only made when and where they are needed. In cancer, this orderly process goes wrong and cells begin to grow and multiply uncontrollably.
Learn more about the causes of breast cancer.
Breast cancer can have a number of symptoms, but usually shows as a lump or thickening in the breast tissue (although most breast lumps are not cancerous). If cancer is detected at an early stage, it can be treated before it spreads to nearby parts of the body.
Learn more about symptoms of breast cancer.
If you notice any of these symptoms, see your GP as soon as possible. After an examination, they may feel it necessary to refer you to a specialist breast cancer clinic for further tests.
Read more information about how breast cancer is diagnosed.
Types of breast cancer
There are several different types of breast cancer, which can develop in different parts of the breast. Breast cancer is often divided into non-invasive and invasive types.
Non-invasive breast cancer
Non-invasive breast cancer is also known as cancer or carcinoma in situ. This cancer is found in the ducts of the breast and has not developed the ability to spread outside the breast. This form of cancer rarely shows as a lump in the breast and is usually found on a mammogram. The most common type of non-invasive cancer is ductal carcinoma in situ (DCIS).
Invasive breast cancer
Invasive cancer has the ability to spread outside the breast, although this does not mean it has necessarily spread. The most common form of breast cancer is invasive ductal breast cancer, which develops in the cells that line the breast ducts. Invasive ductal breast cancer accounts for about 80% of all cases of breast cancer and is sometimes called "no special type".
Other types of breast cancer
Other less common types of breast cancer include invasive lobular breast cancer, which develops in the cells that line the milk-producing lobules, inflammatory breast cancer and Paget's disease of the breast. It is possible for breast cancer to spread to other parts of the body, usually through the lymph nodes (small glands that filter bacteria from the body) or the bloodstream. If this happens, it is known as "secondary" or "metastatic" breast cancer.
The exact causes of breast cancer are not fully understood, but many factors increase the likelihood of developing it, including age and family history of breast cancer.
Women who have a higher-than-average risk of developing breast cancer may be offered screening and genetic testing for the condition. As the risk of breast cancer increases with age, all women aged 50–70 are invited for breast cancer screening every three years. Women over 70 are also entitled to screening and can arrange an appointment through their GP or local screening unit.
Read more information about breast cancer screening.
Treating breast cancer
Breast cancer is treated using a combination of surgery, chemotherapy and radiotherapy. Some cases of breast cancer may also be treated using biological or hormone treatments.
Being diagnosed with breast cancer can affect daily life in many ways. However, there is support available for many aspects of living with breast cancer including emotional, financial and long-term health issues.
One in nine women are affected by breast cancer during their lifetime. There is a good chance of recovery if it is detected in its early stages. For this reason, it is vital that women check their breasts regularly for any changes and always get any changes examined by their GP.
Learn more about how breast cancer is treated.
Find your local cancer support services (including breast screening).
Online Personal Education and Risk Assessment (OPERA)
If you are concerned about your risk of developing inherited breast cancer, you can use Macmillan's online interactive assessment tool, OPERA.
The tool is based on the National Institute for Health and Care Excellence (NICE) guidelines for the classification and care of women at risk of familial breast cancer. It is used by patients and health professionals to assess a person's risk of developing the condition, based on their family history of both breast cancer and ovarian cancer. This is because the genes that are mainly responsible for breast cancer are also linked to ovarian cancer.