Breast cancer is the abnormal growth of cells lining the breast ducts or lobules. These cells grow uncontrollably and have the potential to spread to other parts of the body. Both women and men can develop breast cancer, although breast cancer is rare in men. Most breast cancers are found when they are invasive. Invasive breast cancer means the cancer has spread from the breast ducts or lobules into surrounding breast tissue.
On this page you will find information on:
Types of breast cancer
Invasive breast cancers
The main types of invasive breast cancer are:
- Invasive ductal carcinoma (IDC) – starts in the ducts and accounts for about 80% of breast cancers.
- Invasive lobular carcinoma (ILC) – starts in the lobules and makes up about 10% of breast cancers.
Non-invasive breast cancers
- Ductal carcinoma in situ (DCIS) – Abnormal cells in the ducts of the breast.
- Lobular cancer in situ (LCIS) – Abnormal cells in the lobules of the breast. This is not cancer but increases the risk of developing cancer in either breast. However most women with this LCIS won’t develop breast cancer.
How common is breast cancer?
Apart from non-melanoma skin cancer, breast cancer is the most common cancer found in Australian women – it represents 28% of all cancers in women. Around 17,000 women are diagnosed with breast cancer each year, and one in eight women will be diagnosed with breast cancer by the age of 85.
Although it can occur at any age, it is more common in women over 40. Almost 70% of breast cancers are diagnosed in women aged 40-69, and about 25% in women aged 70 and over. In rare cases, women are diagnosed during pregnancy.
About 140 men are diagnosed with breast cancer in Australia each year and most of these men are over 50.
What are the risk factors?
In most people, the exact cause of breast cancer is unknown, but some factors can increase the risk. Most people with breast cancer have no known risk factors, aside from getting older. Having risk factors does not necessarily mean you will develop breast cancer.
Risk factors include:
- Older age.
- A strong family history, with several first-degree relatives (e.g. mother, sister) diagnosed with breast cancer and/or a particular type of ovarian cancer. However, most women diagnosed with breast cancer do not have a family history.
- Inheriting a mutation in the BRCA1 or BRCA2 genes – more common with Ashkenazi Jewish heritage.
- A previous diagnosis of breast cancer or ductal carcinoma in situ (DCIS).
- A past history of particular non-cancerous breast conditions, such as lobular carcinoma in situ (LCIS) or atypical ductal hyperplasia (abnormal cells in the lining of the milk ducts)
- Regularly drinking alcohol.
- Being overweight after menopause.
- A lack of physical activity.
- Having had radiation therapy to the chest for Hodgkin disease, especially if diagnosed under 30.
- Long-term hormone replacement therapy (HRT) use (slight increase in breast cancer risk).
- Having children and breastfeeding can both slightly reduce breast cancer risk.
Risk factors include:
- Older age.
- A strong family history, with several first-degree relatives (male or female) who have had breast cancer; a relative diagnosed with breast cancer under the age of 40; or several relatives with ovarian cancer or colon cancer.
- Inheriting a mutation in the BRCA1 or BRCA2 genes.
- A rare genetic syndrome called Klinefelter syndrome – men with this syndrome have three sex chromosomes (XXY) instead of the usual two (XY).
What are the symptoms of breast cancer?
If you do have symptoms, they could include:
- A lump, lumpiness or thickening, especially if it is only in one breast.
- Changes to the nipple – such as a change in shape – crusting, a sore or an ulcer, redness, unusual discharge, or a nipple that turns in (inverted) when it used to stick out.
- Changes to the skin of the breast, such as dimpling, unusual redness or other colour changes.
- Changes in the shape of the breast.
- Swelling or discomfort in the armpit.
- Persistent, unusual, pain that is not related to your normal menstrual cycle, remains after your period and occurs in one breast only.
Most breast changes aren’t caused by cancer. However, if you have any symptoms, have them checked by your doctor without delay.
How is breast cancer diagnosed?
If you have symptoms of breast cancer, your GP will take a full medical history, which will include your family history. They will also perform a physical examination, checking both your breasts as well as lymph nodes under your arms and above your collarbones.
To find out if your breast change has been caused by cancer, your GP may arrange some tests, such as a mammogram and biopsy. They may also refer you to a specialist for these and other tests.
- Physical examination – your GP will feel your breasts and the lymph nodes under your arms.
- Mammogram – is a low-dose x-ray of the breast tissue. This x-ray can check any lumps or other changes found during a physical examination. It can also find changes that are too small to be felt during a physical examination.
- MRI scan.
- Biopsy – a small amount of sample cells or tissue is removed from your breast. A specialist doctor called a pathologist examines the sample and checks it for cancer under a microsope.
Other tests include:
- Bone scan – may be done to see if the breast cancer has spread to your bones.
- Blood test – to check your general health and also test your bone and liver function for signs of cancer.
- CT scan.
- Chest x-ray – your doctor may take an x-ray of your chest to check your lungs for signs of cancer.
Some tests may be repeated during or after treatment to check how well the treatment is working. Waiting for the test results can be a stressful time. It may help to talk to a friend or family member, a healthcare professional, or call Cancer Council on 13 11 20.
What is the treatment for breast cancer?
Treatment for early or locally advanced breast cancer aims to remove the cancer and reduce the risk of the cancer spreading or coming back. Treatment may include surgery, radiation therapy, chemotherapy, hormone therapy and targeted therapies.
Your doctors will consider the following factors to recommend the best treatment for you:
- Your test results
- Where the cancer is in the breast
- The cancer’s stage and grade
- Whether the cancer is hormone receptor or HER2 positive or triple negative.
- Your age and general health
- Your preferences.
For more information on the treatment of breast cancer please see our Understanding Breast Cancer booklet.
What is the prognosis?
Prognosis means the expected outcome of a disease. You may wish to discuss your prognosis and treatment options with your doctor, but it is not possible for any doctor to predict the exact course of the disease.
Survival rates for people with breast cancer have increased significantly over time due to better tests and scans, earlier detection, and improvements in treatment methods. Most people with early or locally advanced breast cancer can be treated successfully.
What support is available?
Whether you have been diagnosed with breast cancer, or have a family member or friend who is affected by cancer, there are times when you may need support. Our professional services and support programs are here to help you.
Find out more about:
- Phone support
- Email support
- Cancer counselling
- Practical and financial support
- Support groups
- Information sessions
You don’t have to face cancer alone – we’re here to help.
You can also refer to the Breast Cancer What to Expect guide to help you make sense of what should happen, and to help you with what questions to ask your health professionals to make sure you receive the best care at every step.