The most reliable way to diagnose breast cancer is through a 'triple test'.
If you find a change in your breast that could indicate breast cancer, or a mammogram shows something suspicious, your doctor should refer you to a breast specialist for further investigation using all three of these tests.
The triple test is positive if the result of any component of it is suspicious, indeterminate or malignant (cancerous). If the result of any one test differs from the others then the diagnosis is uncertain and further investigation is required. Only when all three tests are negative (no evidence of cancer) can cancer be ruled out with 99% accuracy.
Medical and personal history and clinical breast exam
Your doctor will examine your breasts for any signs of cancer, and talk to you about your medical and personal history.
Mammogram, ultrasound and sometimes MRI are used to diagnose breast cancer.
A biopsy is the removal of a tissue sample, which is then sent to the laboratory for analysis. This is required to accurately diagnose breast cancer.
Medical and personal history
It’s important to tell your doctor:
- If you’ve noticed any changes to the look or feel of your breasts
- If you or any of your blood relatives have had breast or ovarian cancer
- If you’ve had any previous breast surgery or biopsies
- If you take, or have taken, medications such as HRT or oral contraceptives
- If you have any history of radiotherapy to the chest
- If you have Ashkenazi Jewish ancestry (are of Ashkenazi Jewish descent)
A thorough examination of both breasts is performed by a medical professional and should also include examination of your axillae (armpits) and around the collarbone near your neck to check for enlarged lymph nodes.
Mammogram and Ultrasound
If you are aged over 35 breast imaging will involve a diagnostic mammogram (breast x-ray) and an ultrasound. A diagnostic mammogram (used to evaluate an abnormality) is the same as a screening mammogram, except that a few extra views will be taken (a screening mammogram only take two views – one from above, and one from the side).
If you are aged under 35 a mammogram may be more difficult to read due to the natural density of your breast tissue, so an ultrasound will be performed first. An ultrasound uses sound waves to produce a picture of the breast tissue and can distinguish between solid and fluid-filled lesions. A diagnostic mammogram would also be performed if something abnormal is seen on the ultrasound.
Tomosynthesis (3D mammography)
This can sometimes be used in conjunction with conventional 2D digital mammography. Tomosynthesis takes multiple pictures from many angles to construct a three-dimensional image of the breast, and can improve the rate of cancer detection and reduce unnecessary biopsies. Tomosynthesis is not yet available in all centres.
Magnetic Resonance Imaging may be used in some cases. Though there is some uncertainty over its value in breast cancer diagnosis, it's often used to evaluate the true size and extent of cancers which are not well seen on mammograms, and particularly with lobular cancer, to ensure the cancer is confined to just one breast. MRI is also useful in the evaluation of dense breasts in young women; lesions that can be felt but are not seen on other imaging; or when breast cancer cells have been found in underarm lymph nodes but no tumour can be seen in the breast on other imaging. It can also add important information regarding lesions seen on a mammogram.
MRI builds a picture of the breasts using magnetism and radio waves, and a contrast injection of a substance called Gadolinium may be given to improve the clarity of the images.
Breast MRI requires highly specialised equipment and radiologists, and may not be available outside of the main treatment centres.
Biopsies are used to diagnose an area of abnormality. A sample of cells/tissue is removed from the area of concern, usually under the guidance of an ultrasound, and sent to a laboratory for analysis.
There are several types of biopsy and it may be necessary to have more than one type.
Biopsies performed in the clinic or radiology rooms
Fine needle aspiration (FNA)
A fine needle is inserted into the breast, usually with ultrasound guidance, and cells are aspirated from the area using a syringe. This method can identify cancer cells but not the specific type of cancer, and is not able to identify pre-invasive cancer (DCIS). FNA is also used to drain fluid-filled cysts, and is easily performed in the doctor’s rooms.
This technique uses a device with a spring-loaded hollow needle to remove small samples or 'cores' of tissue from a solid lump, enabling a pathologist to accurately identify the cells and provide a diagnosis.
Local anaesthetic is used to numb the breast, and the core biopsy is performed in the breast clinic or in the radiology rooms under ultrasound guidance. This is the most commonly used breast biopsy technique as it can provide a tissue diagnosis, distinguish between invasive and pre-invasive cancer, and can provide information about tumour grade and receptors.
Stereotactic core biopsy
This procedure is used when a mammogram has identified an abnormality, but the area can’t be felt on physical examination or located using ultrasound.
Often it’s used when calcifications are seen in the breast, which appear like grains of salt on mammography. Most of these are benign but some shapes and patterns may represent an early sign of cancer. If these are classified as indeterminate or suspicious, a radiologist uses specialised mammography equipment and a computer to locate the abnormality.
Local anaesthetic is used to numb the breast, which is compressed in the mammogram machine with the patient either lying or sitting. Stereotactic mammography precisely pinpoints the location of a breast abnormality by using computer analysis of x-rays taken from two different angles.
The area of concern is then targeted using a needle which is directed into the area to collect a tissue sample while the breast is held still. The sample will be x-rayed to make certain that the correct tissue has been collected before being sent to the laboratory.
Stereotactic core biopsy is performed in a radiology clinic.
Biopsies performed in the operating theatre
Wire localisation biopsy
This method is used when imaging has shown an area that needs to be removed but can’t be felt by the surgeon or it may be too small to target with a biopsy in the clinic. A fine wire with a small, hooked end (a hookwire) is used to guide the surgeon to the correct area.
Using local anaesthetic to numb the tissue, the wire is inserted into the area of concern, guided by mammogram or ultrasound. The wire is then taped to the skin to secure its position and the patient is transferred to the operating theatre where the surgeon is able to remove the area of abnormality along with the wire.
Open surgical biopsy (excision biopsy)
An excision biopsy may need to be performed if a firm diagnosis has not been made using the other methods. The area of abnormality is surgically removed and sent to the laboratory for analysis. Generally this procedure is performed in a ‘day stay’ hospital.
After the biopsy has been completed, a very small titanium marker clip may be put in your breast at the biopsy site. This enables the exact area to be identified on future imaging or in case of further surgery. Adverse reactions to the clips are very rare.
Tissue removed with a biopsy procedure will, in all cases, be microscopically examined by a pathologist who will identify the tissue and prepare a report of the findings.