How is breast cancer diagnosed?

Breast cancer is diagnosed by physical examination, mammogram, scans, taking a sample of cells from the lump, biopsy or removal of the lump, and laboratory testing on any breast tissue samples. In some cases other scans or tests may be required. Your general practitioner may arrange these tests or you may be referred directly to a specialist.

What are the symptoms of breast cancer?

Breasts undergo changes throughout a woman's life, particularly the normal changes experienced during the menstrual cycle. 

Some breast changes may be early signs of breast cancer, including:

• a lump or lumpiness
• thickening of the tissue
• nipple changes, for example:
  -a blood-stained discharge from one nipple
  -an inverted nipple (unless the nipple has always been turned in)
  -a rash on a nipple
• skin dimpling
• a change in shape 
• a painful area
• a rash or red marks which appear only on the breast.

Although these changes do not necessarily mean you have breast cancer, any breast change should be checked by a doctor.

Physical examination

The doctor will take your medical history and examine your breasts.

Diagnostic imaging

Mammogram
A mammogram is a breast x-ray. It will give your doctor more information about any lump or other change noticed. Occasionally, a lump that can be felt is not seen on a mammogram. Such a lump should not be ignored. Other tests will need to be done.

Ultrasound
An ultrasound is a test using high frequency sound waves to help detect lumps or other changes.

Magnetic resonance imaging (MRI)
An MRI scan is a scan that uses magnetic resonance to detect abnormalities in the breast. This type of scan is sometimes used in lobular carcinomas to make sure there is not more than one cancer present, and it can check the other breast as well. It can also be used to check the breast if a mammogram is negative but the specialist is concerned about the lump or changes in the breast.

Fine needle aspiration

A fine needle aspiration can be done in your specialist's rooms, a hospital outpatient department, or at a laboratory by a pathologist. A very narrow needle is used to take some cells from the lump. These cells are then sent to a laboratory for examination.

A fine needle aspiration may cause a little discomfort but is not usually any more painful than a blood test. Results from this test may be available immediately or take some time, depending on where it is done.

Biopsy

Sometimes a biopsy will be necessary. A biopsy is the removal of a sample of a lump or the entire lump for examination under a microscope.

Core biopsy

A larger needle than that used for fine needle aspiration is used to obtain a sliver of tissue from the lump. This is done with a local anaesthetic. Core biopsy can be done by a radiologist under ultrasound guidance or in a mammogram machine (stereotactic core biopsy). Sometimes it is done by palpation (feeling) of the lump by the specialist.

Open biopsy

Sometimes, a surgical or open biopsy is necessary to remove the whole lump. This small operation is usually done under general anaesthetic, although occasionally a local anaesthetic is all that is needed. To have an open biopsy, you may need to stay in hospital overnight.

Hook wire biopsy

If the abnormality in the breast can only be detected by the mammogram (your doctor cannot feel the lump), a guide wire may be inserted in the breast to mark the area of the breast to be removed in the biopsy. This procedure takes place in the radiology department.

The placement of the wire is done under local anaesthetic, and the abnormality is then removed as in an open biopsy under general anaesthetic, and sent to the laboratory for testing.

Hormone-receptor tests

If the lump is a cancer, hormone tests will be done using immuno-histochemistry (IHC), on the sample that was removed. These tests show whether the cancer cells have special 'markers' on them called 'hormone receptors' (oestrogen/progesterone). If these markers are present, the cancer is described as 'hormone receptor positive' and the cancer is more likely to respond to hormone treatment if this is needed later.

HER2 tests

HER2 is a growth factor protein which tells breast cancer cells to grow. Approximately one in five women with breast cancer test 'HER2 positive', which means their cancer is more aggressive.

Two tests (IHC and FISH) are available to check HER2. The IHC test is used first and if this is only weakly positive, then the FISH test is used. If tests show that you have HER2 positive cancer, this will influence future choices of chemotherapy, hormones, or monoclonal antibodies. A monoclonal antibody drug called trastuzumab (Herceptin) targets the growth factor so that breast cancer cells stop growing.

Staging breast cancer

'Staging' is a process of assessing the extent of a tumour. Other tests may also be necessary if cancer is diagnosed. These include blood tests and a chest x-ray. In some situations a bone scan and a liver scan may be done.

The complete results from the biopsy and any further tests will help to determine the best treatment for you. With this information your doctors will know if you have an early breast cancer, locally advanced breast cancer, or metastatic (secondary) breast cancer.

Grading breast cancer

The pathologist (doctor who looks at cancers in the laboratory) ‘grades’ the cancer, from 1 to 3, according to the way the cancer cells look and behave.

The cells of a Grade 1 breast cancer look more like normal breast cells, whereas the cells of a Grade 3 breast cancer look very abnormal, indicating a faster-growing cancer.

The treatment choices you are offered will be based on all the information the doctor has about your cancer.

Related topics

Also see Breast cancer treatment and Breast cancer and Breast screening: mammograms

What does that term mean? See Cancer glossary

Original material provided by the Cancer Society, June 2007. Reviewed by everybody, July 2010.