Breast cancer is the most common cancer in women and the second most common cancer to cause death in women, after lung cancer. It is uncommon in males.
The risk of being diagnosed with breast cancer by age 85 is 1 in 8 for women and 1 in 838 for men.
Breast cancer symptoms
The symptoms can include:
- new lumps or thickening in the breast or under the arm
- nipple sores
- nipple discharge or turning in
- skin of the breast dimpling
- rash or red swollen breasts.
Pain is rare.
Causes of breast cancer
The causes of breast cancer are unknown, but risk factors include:
- increasing age
- family history
- inheritance of mutations in the genes BRCA2, BRCA1 and CHEK2
- exposure to female hormones (natural and administered)
- obesity (poor diet and inadequate exercise) and
- excess alcohol consumption.
There is also an association with some benign breast disease and past exposure to radiation.
Screening for breast cancer
Women aged between 50 and 74 are invited to access free screening mammograms every two years via the BreastScreen Australia Program.
Women aged 40-49 and 75 and over are also eligible to receive free mammograms, however do not receive an invitation to attend.
It is recommended that women with a strong family history of breast or ovarian cancer, aged between 40 and 49 or over 75 discuss options with their GP.
Diagnosis for breast cancer
If your doctor suspects you may have breast cancer, you will have one or more of the following tests:
A mammogram is an x-ray that can find changes that are too small to be felt during physical examination.
A doctor removes some of the breast tissue for examination under a microscope.
If cancer is detected in your breast, you may have other scans to see if the cancer has spread to other parts of your body, such as a CT scan or MRI scan.
Treatment for breast cancer
Treatment depends on the extent of the cancer.
Staging involves assessing the size of the breast cancer and whether it has spread to the draining lymph nodes under the arm. A CT scan of the chest and liver and bone scan are done to check the sites to which breast cancers most commonly spread.
For localised breast cancer, the most extensive surgical option is to remove the breast and lymph nodes under the arm. When part of the breast is removed it is referred to as breast conserving surgery. When the whole breast is removed it is called a mastectomy.
However, removing the lump and just a section of the breast, followed by radiotherapy, results in the same rate of survival. If the first draining lymph node can be identified using dye or a nuclear medicine scan, it can be sampled and if it is negative, further surgery avoided.
For tumours at greater risk of recurrence ie. bigger, more aggressive cancers, or cancers that have spread to the lymph nodes, additional treatment (adjuvant therapy) can be given after surgery.
This can include hormone therapy of aromatase inhibitors or tamoxifen for women whose tumours have hormone receptors on their surfaces, and chemotherapy and targeted therapies such as trastuzumab for those 25 per cent of tumours that are HER2 positive (ie. have the target for trastuzumab on their surfaces).
Patients presenting with locally extensive cancer will have chemotherapy and radiotherapy initially to see if it will shrink the cancer to make it operable.
Treatment for recurrent disease
If breast cancer returns after initial treatment, local disease may be treated with surgery, while more widespread disease will be treated with combinations of similar drugs to those used in adjuvant treatment. Common chemotherapy drugs include anthracyclines and taxanes.
Patients with bone disease can receive bisphosphonates such as zoledronate to slow the erosion of bones, and receive local radiotherapy for pain.
Although it is most often used by people with advanced cancer, palliative treatment can be used at any stage of cancer treatment. It is intended to improve a person’s quality of life by alleviating the symptoms of cancer, without trying to cure the disease. It can include pain relief, and the management of other physical and emotional symptoms.
Depending on your treatment, your treatment team may consist of a number of different specialist staff, such as:
- a radiation oncologist
- a radiation therapist
- a medical oncologist
- a breast care nurse
- a surgeon
- a reconstructive (plastic) surgeon
- lymphoedema therapist
- other allied health professionals, such as counsellor and physiotherapists.
Prognosis for breast cancer
It is not possible for a doctor to predict the exact course of a disease, as it will depend on each person’s individual circumstances. However, your doctor may give you a prognosis, the likely outcome of the disease, based on the type of breast cancer you have, the test results, the rate of tumour growth, as well as your age, fitness and medical history.
The most common types of breast cancer have a very good long-term prognosis, especially if the cancer is found early. If the cancer is limited to the breast, 96% of patients will be alive five years after diagnosis; this figure excludes those who die from other diseases. If the cancer has spread to the regional lymph nodes, five year relative survival drops to 80%. The overall five year survival rate for breast cancer in females is 89%.
Preventing breast cancer
There is no proven method of preventing breast cancer, however the risk of breast cancer can be reduced by lowering alcohol consumption and maintaining a healthy weight.
Women who are at high risk because of a very strong family history may benefit from hormones such as tamoxifen, usually administered over five years. Bilateral prophylactic mastectomy can be considered in women at high risk of breast cancer due to gene mutations.