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Breast cancers are tumours that arise from the uncontrolled growth of cells in the breast. They occur in the ducts that transport milk to the nipple during breast feeding (lactation) or in the lobules, the glands that produce milk.
Each breast cancer has its own characteristics. Some are slow-growing; others can be aggressive. Some cancers are sensitive to the hormones oestrogen and progesterone, while others can over-express certain proteins. The cancer's characteristics can affect treatment choices and the potential for the cancer to recur.
In 2017, it is estimated that the risk of an individual being diagnosed with breast cancer by their 85th birthday will be 1 in 14 (1 in 715 males and 1 in 8 females). The Australian Institute of Health and Welfare estimates that 18,235 new cases of breast cancer (148 males and 18,087 females) will be diagnosed in 2018. The estimated number of death from breast cancer in 2018 is 3,157 (28 males and 3,128 females). The rest of this article will focus on breast cancer in women. It is recommended that men who have been diagnosed with breast cancer speak to their healthcare provider for information specific to them.
RISK FACTORS FOR BREAST CANCER
Breast cancer can develop at any age, but the risk of developing it increases as women get older. The majority of cases develop for reasons we do not yet understand. Some of those at higher risk of developing breast cancer include women:
- With close relatives (mother, sister, aunt) who have had the disease
- Who have had a cancer in the other breast
- Who have not had children
- Who had their first child after the age of 30
- With an inherited mutation in breast cancer genes, usually either BRCA1 or BRCA2. About 5% to 10% of breast cancers are related to these mutations. BRCA1 and BRCA2 are two tumour suppressor genes that help prevent cancer by producing proteins that suppress abnormal cell growth. Mutations in these genes can affect their normal function, potentially allowing uncontrolled cell growth and increasing the risk of cancer. Women with inherited BRCA1 or BRCA2 mutations have up to an 85% lifetime risk of developing breast cancer.
A healthy lifestyle that includes regular exercise, maintaining a healthy body weight, and avoiding alcohol may help to minimise the risk of developing breast cancer. Research studies continue to identify factors that are associated with an increased or decreased risk of developing the disease, but there is no single set of actions that will cause or prevent breast cancer. Family history and exposure to oestrogen are among the most important factors in breast cancer risk. Women should work with their doctor to determine their personal risk factors and how to address them.
For those women who have a gene mutation such as BRCA1 and BRCA2 that is frequently associated with breast cancer, prophylactic mastectomy is an option. Women electing this option choose to have both breasts removed before developing cancer rather than run the high risk of developing the disease later in their lifetime. Studies have shown that such surgery can reduce the risk of developing breast cancer by up to 97%. Other women elect to have a prophylactic mastectomy on their cancer-free breast after developing cancer in the other breast. A doctor can help advise and work with a woman who is considering prophylactic mastectomy.
SIGNS AND SYMPTOMS OF BREAST CANCER
It is important to remember that most lumps found in the breast are not cancerous but are benign and that the signs and symptoms associated with breast cancer may be due to other causes. Some signs and symptoms include:
- Lump in the breast
- Breast skin dimpling, reddening, or thickening
- Nipple retraction
- Breast swelling or pain
- Nipple pain and/or discharge
- Swelling or lumps in underarm lymph node
- Pigmented, peeling, scaling or flaking skin in the area around the nipple
- Changes in size, shape or appearance of the breast
A rare form of breast cancer, inflammatory breast cancer (IBC), does not form a lump. Some of the symptoms of this condition can be similar to those of a breast infection, with warmth, tenderness, breast swelling, itching, and ridged thickened skin.
Last Review Date: August 1, 2018