Breast cancer is a tumour in the breast created by an abnormal and uncontrolled growth of cells.
Breasts are made up of fat, connective tissue and gland tissue divided into lobes. The lobes produce breast milk, which is carried to the nipple by connecting ducts.
Breast tissue goes into your armpit where there are lymph nodes. These are glands that are part of your immune system.
Most women have breasts of different sizes which look and feel different at certain times of the month, depending on their menstrual cycle. Your breasts also change during the different stages of your life; for example, after the menopause, they become less full or dense.
Breast cancer is the most common cancer to affect women in Australia (excluding non-melanoma skin cancer), accounting for over 25% of all cancer diagnoses. Approximately eight out of 10 women who develop breast cancer are over 50.
Men can also develop breast cancer but this is rare.
Breast cancer usually starts in the cells lining the ends of the lobes and in the ducts themselves. It can spread from there into the breast tissue and lymph nodes.
The two main types of breast cancer are described below.
Non-invasive breast cancers are cancers that stay within the ducts or lobes of your breast and don't spread to surrounding tissue or to other parts of the body.
The most common type of non-invasive breast cancer is ductal carcinoma in situ (DCIS). This is a very early type of breast cancer where the cancer cells are only found inside the milk ducts and haven't spread into the breast tissue.
In some cases, DCIS can develop into an invasive form of breast cancer.
Invasive breast cancers are cancers that have spread from the ducts or lobes of your breast into the surrounding tissue. Invasive cancer most commonly starts in the ducts and spreads to other parts of the breast. Less commonly it starts in the lobes.
The causes of breast cancer aren’t yet fully understood. However, there are certain factors that make developing breast cancer more likely.
You're more likely to develop breast cancer if you:
You may also have an increased risk of developing breast cancer if you:
There is a small increase in the risk of breast cancer for women who use combined oral contraceptives or hormone replacement therapy (HRT). Talk to your doctor about the risks and benefits of these medicines to you before starting any treatment, or if you are concerned about your current treatment with these medicines.
There are also factors that appear to decrease your risk of developing breast cancer:
However, there are inherent risks to pregnancy and birth. These are higher than the slight additional risk of breast cancer, so it's not recommended you have children just to reduce your risk of breast cancer.
Maintaining a healthy weight, getting regular exercise and not drinking excessive amounts of alcohol may help to protect against breast cancer.
Some women won't notice any changes in their breasts and breast cancer is only found when they undergo breast screening.
However, many women will notice a breast lump or a change in the overlying skin or nipple. About nine out of 10 breast lumps are benign (non-cancerous), but if you do find a lump, you should see your GP straight away.
There are also other symptoms to look out for:
These symptoms may be caused by problems other than breast cancer. If you have any of these symptoms, visit your GP for advice.
All women are at risk of developing breast cancer. Having certain risk factors may increase your chance of developing the condition. While you can’t change some of these like your age or family health history, some of these factors are things in your control.
There are also things you can do to detect breast cancer early, if it does happen, and this can mean a greater range of treatment options and may improve your chances of survival.
The BreastScreen Australia program invites all women between the ages of 50 and 74 for a free breast screening every two years. Women aged 40 and over can also be screened in this program for free. Breast screening means having a mammogram. This can help to show very early signs of any cancer.
You can also check your breasts regularly yourself, and you can do this at any age, even if you’re having regular mammograms.
Be aware of how your breasts normally look and feel, this can be easily done as part of your everyday such as when showering or dressing, so you can spot any changes quickly. See your GP straight way if you notice any changes in your breasts.
Your GP will ask about your symptoms and examine you.
Your GP may refer you to a specialist breast clinic where you're likely to have further tests. The most common tests are:
If you're found to have cancer, you may need to have other tests to assess if the cancer has spread. The process of finding out how big the cancer is and which parts of the body are affected is called staging.
The tests might include blood tests and a chest X-ray. Your doctor may also arrange for you to have a scan such as a CT (computerised axial tomography) or MRI (magnetic resonance imaging) scan. These scans produce images of the inside of your body and can help your doctor to see if the cancer has spread.
You may also have a test to see if the breast cancer cells you have are positive for a certain protein or hormone receptor, and will respond to hormone or biological treatment.
There are a number of different treatments available for breast cancer and you may have more than one of them.
The treatment you have will depend on a number of factors, such as your age and general health, what type of cancer you have, whether your cancer has spread, what stage it is at, whether or not you have been through menopause and whether you’ve had breast cancer before.
Some women may also want to consider the effects of the treatment in their considerations. Most cancer treatments work by destroying cancer cells, but they can also affect healthy cells which may cause side effects such as:
Your doctor will talk to you about the treatments available to you, and help you decide on what is most appropriate for you taking into account your personal preferences.
The first-line treatment for most people with breast cancer is usually surgery. Depending on the size and position of your breast lump, your surgeon may suggest either a lumpectomy or a mastectomy.
A lumpectomy is where the lump is removed, usually with some healthy tissue around it.
A mastectomy is where the whole of your affected breast is removed. You may be offered surgery to have your breast reconstructed afterwards.
With both of these procedures, some lymph nodes may also be removed from your armpit. This is to see whether the cancer has spread.
After surgery, you may have other treatments, such as radiotherapy. These treatments can help to reduce the chance of the cancer coming back or spreading.
Radiotherapy is a treatment to destroy cancer cells with radiation. A beam of radiation is targeted on the cancerous cells, which shrinks the tumour.
Radiotherapy is often used to treat breast cancer, usually after a lumpectomy. It may also been given after a mastectomy although the benefit of this treatment after a mastectomy is not so clear cut. Your doctor or surgeon can advise you on this.
You're likely to need a course of radiotherapy that lasts for three to five weeks. Radiotherapy is given as out-patient treatment and each treatment only takes a few minutes but you will need to attend five days a week.
Chemotherapy uses medicines to destroy cancer cells. You may have chemotherapy:
Some chemotherapy can be taken as a tablet, but generally it is given as an injection into your vein. You may need one or more different medicines as part of your treatment.
You will usually have chemotherapy as a treatment cycle, with a few days taking the medicine(s) and then a few weeks of rest afterwards. You may have a number of treatment cycles over a period of up to eight months.
Hormones, such as oestrogen, can affect the growth of breast cancer cells. Taking medicines that block these hormones can treat some kinds of breast cancer.
Hormone therapies are usually used after you have had surgery, though they can be used before surgery or to treat cancer that has come back.
Women usually take hormonal treatments for at least five years following initial treatment for breast cancer.
There are several types of hormone therapy. Talk to your doctor about what is the right medicine for you.
Biological therapy (also known as targeted therapy) is treatment with monoclonal antibodies that stimulate your body to attack or control the growth of cancer cells. Antibodies are proteins produced by your immune system that usually fight against bacteria and viruses. Monoclonal antibodies are made in a laboratory and are designed to seek out particular cells.
The most commonly used biological therapy is called trastuzumab (Herceptin®). It works by targeting breast cancer cells that have a particular protein on their surface called HER2. Trastuzumab is given into your vein via a drip.
If your breast cancer returns, you may be given another biological therapy that targets HER2 called lapatinib (Tykerb®).
These therapies only work if you have breast cancer that produces the HER2 protein. About 20 percent of people have this type of cancer, known as HER2-positive breast cancer.
Another biological therapy that may be used if your breast cancer returns is bevacizumab (Avastin®). This therapy works by blocking another protein that is known to be involved in breast cancer called VEGF (vascular endothelial growth factor). Bevacizumab is also given into your vein via a drip.
After your treatment has finished, your doctor will ask you to have regular check-ups. He or she will ask if you have any symptoms and may also arrange for you to have blood tests and mammograms. This is to check for signs of the cancer coming back.
If you're well, you will need fewer check-ups as time goes on. If you have any symptoms in between your appointments or are worried at all, speak to your doctor.
Finding good support if you or someone close to you has cancer is important. Being diagnosed with cancer can be distressing. Having support to deal with the emotional and physical aspects of living with cancer can make it easier to cope.
Don’t be embarrassed or afraid to reach out to family, friends or your health professionals for help and support. Specialist cancer doctors and nurses are also able to provide support. You may also find it helpful to see a counsellor.
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Last published: 31 October 2012