Breast cancer is an abnormal growth of cells in the breast. There are different types of breast cancer, but they all start in the milk ducts or the milk lobules (milk producing glands). It may grow into surrounding tissues and spread to other organs of the body.
Breast cancer is the most common form of cancer in Australian women. Around one woman in every eight is diagnosed with breast cancer before the age of 85, according to government statistics. Whilst we should be responsible about looking after our breast health, it is important to remember many more women die of heart disease and stroke in Australia than die of breast cancer.
Who is most at risk of developing breast cancer?
- Women over 50-75% of breast cancers occur in women over the age of 50
- Women who have had a previous breast cancer
- Women with a mother, daughter or sister who has had breast cancer
Other factors that may increase the risk include:
- having dense breasts
- being overweight
- drinking alcohol
If you are concerned about your risk of breast cancer, talk to your doctor.
Breast cancer diagnosis
If you find a lump in your breast, you should see your doctor.
Your doctor may refer you to a breast specialist. The specialist may conduct tests to determine whether your lump is benign (harmless) or cancerous. They will usually:
- feel the lump
- take a mammogram or an ultrasound of your breast
- conduct a needle biopsy where the specialist inserts a needle into your breast under local anaesthetic and takes a small sample of tissue to test for cancer
If any of these three tests (known as the triple test) causes concern, your specialist will recommend further investigation and perhaps removing the lump.
The key message with any breast lump is to see your doctor promptly to clearly explain what is worrying you and to ask for information. Early diagnosis is the key to successful treatment.
Size & breast cancer
The risk of developing breast cancer has nothing to do with the size of your breasts. Whilst women who are overweight tend to have larger breasts, their breast size is not relevant to their breast cancer risk. Rather, it is the excess body fat which increases oestrogen production in the body that is linked to breast cancer.
Postmenopausal breast cancer
In a number of studies, higher Body Mass Index (BMI) and postmenopausal weight gain have been associated with a higher risk of developing breast cancer in postmenopausal women.
- Women who weighed more than 80kg had a 25% higher risk of developing breast cancer compared to those weighing less than 60kg
- Women who had gained 10kg or more since menopause had an 18% higher risk of developing breast cancer compared with women who maintained their weight
This result is likely to be because of higher circulating levels of oestrogens in women who have more fat tissue. Fat tissue produces oestrogen, which is linked to breast cancer.
Breast injury & breast cancer
Breast injury may cause scarring or damage to the fatty tissue but it is not known to cause breast cancer.
Injury can cause tenderness and many women are concerned pain is a feature of breast cancer. Breast tenderness is usually due to benign (non-cancerous) breast disease. This includes many common conditions including breast pain, breast lumps or nipple discharge. The most common cause of breast nodularity (lumps) and tenderness is fibrocystic change (thickening breast tissue), which occurs in approximately 60% of premenopausal women. These conditions do not increase the risk of breast cancer.
Breast cancer & menopausal symptoms
Menopausal symptoms and breast cancer are associated for a number of reasons:
- Cancer treatment can cause ovaries to fail and you start menopause
- You may be in menopause when you are diagnosed with breast cancer
- Adjuvant endocrine therapy, which works to prevent breast cancer recurrence, can cause menopausal symptoms
- Stopping hormone replacement therapy (HRT) when your breast cancer diagnosis is made can cause menopausal symptoms that may have been masked by HRT
Menopausal symptoms may start abruptly with breast cancer treatment or advance slowly; there is no way of predicting how menopause will affect each woman. More information is available in our pages on menopause after cancer.
Breast cancer & osteoporosis
Women who develop breast cancer may be at risk of developing osteoporosis, a condition in which bones become fragile and brittle. It's important for women who have been diagnosed with breast cancer to check their bone health, especially if they have other risk factors for osteoporosis.
For women who are diagnosed with osteoporosis, there are therapies available which can treat this condition. Weight resistant exercises and adequate calcium in your diet as well as vitamin D are an important part of managing osteoporosis.
Premenopause & osteoporosis
Premenopausal women often become prematurely menopausal because chemotherapy may lead to ovarian failure.
Once the ovaries stop functioning bone loss occurs, particularly at the spine. In the first 12 months after chemotherapy, bone loss in the spine is approximately 3-4%. Even though this bone loss may occur, it does not necessarily lead to osteoporosis.
If ovarian failure does not occur after chemotherapy, bone density or strength tends to remain stable.
Premenopausal women who are given tamoxifen, (sold as Nolvadex, Genox, Tamosin, Tamoxen) also experience a progressive loss of bone from the spine, but not as great. They experience a loss of bone in the spine of approximately 1.4% per year. Tamoxifen works by partially suppressing the body's production of oestrogen. It has anti-oestrogen effects in the breast, but it continues to have oestrogen like effects in bone and this protects against bone loss.
Postmenopause & osteoporosis
The effect of cancer treatment on bone for postmenopausal women is slightly different to that of premenopausal women. Chemotherapy for postmenopausal women results in loss of bone density or strength. Tamoxifen results in an increase in bone density in the spine of approximately 1.2% per year.
Tamoxifen has a desirable effect on bone density in postmenopausal women. However, a report has found there is a slightly increased rate of fracture in this group compared to the normal population, despite the increases in bone density. More research is needed in this area.
Aromatase inhibitors & osteoporosis
Aromatase inhibitors are prescribed in Australia for postmenopausal women whose breast cancer has spread beyond the breast and lymph nodes. These drugs work by virtually suppressing all oestrogen production in the body. The studies with one of these drugs known as anastrozole (sold as Arimidex), has shown that it does lead to loss of bone density at the spine and hip. This effect seems to be more significant in women who are newly menopausal. There is also a very slightly increased risk of fracture for women taking this medication, although further research is needed in this area.
Depression & anxiety
Some women are depressed and anxious in the first years after breast cancer is diagnosed and about 25% of women remain depressed four years after their diagnosis.
Younger women with breast cancer experience more physical symptoms, psychological distress and poorer sexual functioning compared to other breast cancer age groups.
The experience of depression and anxiety with breast cancer is often affected by:
- the stage you are dealing with - if a tumour has been removed or is shrinking compared with if a tumour is growing or has returned
- the treatment you need – such as surgery or chemotherapy and the demands this places on you psychologically
- the support you find from family and friends
- whether you have previously experienced any depression or anxiety that might be brought back to life when dealing with your breast cancer diagnosis and treatment
When to see your doctor
If you have symptoms of anxiety and depression please see your doctor as there are a range of treatments available to help you.
Last updated 11 October 2017 — Last reviewed 30 January 2014
This web page is designed to be informative and educational. It is not intended to provide specific medical advice or replace advice from your health practitioner. The information above is based on current medical knowledge, evidence and practice as at January 2014.