How is breast cancer diagnosed?

A mammogram is a low-dose x-ray of the breast tissue. It can check any lump or other breast changes found during a physical examination. It can also show changes that are small or can’t be felt during a physical examination. If you have breast implants, it’s important to let staff know before you have the mammogram.

Your breast is placed between two x-ray plates. The plates press together firmly for a few moments to spread the breast tissue out so that clear pictures can be taken. You will feel some pressure, which can be uncomfortable. Both breasts will be checked.

Tomosynthesis – Also known as three-dimensional mammography or digital breast tomosynthesis (DBT), tomosynthesis takes x-rays of the breast from many angles and uses a computer to combine them into a three-dimensional (3D) image. Tomosynthesis may be better for finding small breast cancers, particularly in dense breast tissue.

An ultrasound uses soundwaves to create a picture of breast tissue. It is often done if a mammogram picks up breast changes, or if you or your GP can feel a lump.

The person doing the ultrasound will spread gel on your breast, and then move a small device called a transducer over the breast area and armpit. This sends out soundwaves that echo when they meet something dense, like an organ or a tumour. A computer creates a picture from these echoes. The scan is painless and takes 15–20 minutes.

A magnetic resonance imaging (MRI) scan uses a large magnet and radio waves to create pictures of the breast tissue on a computer. Breast MRI is mainly used for people who are at high risk of breast cancer or who have very dense breast tissue or breast implants. It may also be used if other imaging test results are not clear or to help plan breast surgery.

Before the MRI, you will usually have an injection of a contrast dye to make any cancerous breast tissue easier to see. You will lie face down on a table with cushioned openings for your breasts. The table slides into a large machine, shaped like a cylinder. The scan can take 30–40 minutes. It is painless but loud, so you’ll wear earplugs. Some people feel claustrophobic. If you think you may feel anxious, speak to your doctor before the appointment. You may be offered a mild sedative.

If breast cancer is suspected, a small sample of cells or tissue is taken from the lump or area of concern. A specialist doctor called a pathologist  checks the sample under a microscope for any cancer cells.

There are different ways of taking a biopsy and you may need more than one type. The biopsy may be done in a specialist’s rooms, at a radiology practice, in hospital or at a breast clinic. Bruising and soreness to your breast is common after any type of biopsy.

Core biopsy – The piece of tissue (a core) is removed with a needle. Local anaesthetic is used to numb the area, and a mammogram, ultrasound or MRI scan is used to guide the needle into place.

Vacuum-assisted core biopsy – A needle attached to a suction-type instrument is inserted into a small cut in the breast. A larger amount of tissue is removed with a vacuum biopsy, making it more accurate in some situations. The needle is usually guided into place with a mammogram, ultrasound or MRI. This biopsy is done under a local anaesthetic, but you may feel some discomfort.

Fine needle aspiration (FNA) – A thin needle is inserted into an abnormal lymph node or other tissue, often with an ultrasound to help guide the needle into place. A local anaesthetic may be used to numb the area where the needle is inserted.

Surgical biopsy – If a needle biopsy is not possible, or if the biopsy result doesn’t provide a clear diagnosis, you may have a surgical biopsy to remove all or part of a lump. A wire or other device is inserted to act as a guide during the surgery, and then the tissue is removed under general anaesthetic. This is usually done as day surgery.

If tests on the biopsy sample show that you have breast cancer, you may have further tests to check whether the cancer has spread to other parts of your body. Not everyone will need all these tests.

Blood tests – A blood sample may be taken to check your general health, bone marrow and liver function, and to test for specific tumour markers.

Bone scan – A bone scan may be done to see if the breast cancer has spread to your bones. A small amount of radioactive material is injected into a vein, usually in your arm. This material is attracted to abnormal areas of the bone. After a few hours, the bones are viewed with a scanning machine, which sends images to a computer. A bone scan is painless and the radioactive material is not harmful. You should drink plenty of fluids the day of the test and the day after it.

CT scan – A CT (computerised tomography) scan uses x-ray beams to take pictures of the inside of the body. It looks for signs that the cancer has spread. Before the scan, you will be given an injection of dye into a vein in your arm. This dye, called contrast, makes the pictures clearer. For the scan, you lie flat on a table while the CT scanner, which is a large doughnut shape, takes pictures. It is painless and takes about half an hour.

PET scan – In a PET (positron emission tomography) scan, a small amount of low-level radioactive solution is injected into a vein in the arm or hand.  Any cancerous areas take up more of the radioactive solution and show up brighter in the scan.

Before a scan, tell the doctor if you have any allergies or had a reaction to dyes during previous scans. Also tell them if you have diabetes or kidney disease or are pregnant or breastfeeding.

If tests on the biopsy sample show that it is breast cancer, extra tests will be done to work out the features shown here and help plan treatment. The results will be included in the pathology report. 

Hormone receptor status – ER+ and/or PR+ = 70-80% of all breast cancers

The hormones oestrogen and progesterone are produced naturally in the body. A receptor is a protein on the surface of the cell. Normal breast cells have oestrogen receptors (ER) and progesterone receptors (PR). Breast cancers that have too many of these receptors are known as ER positive (+) or  PR positive (+). This lets more oestrogen or progesterone enter the cell, where it stimulates cancer cell growth.

ER+ and PR+ cancers are usually treated with hormone therapy drugs (or endocrine therapy) that block the receptor, or drugs that reduce the amount of hormones that the body makes (aromatase inhibitors). If the cancer has low levels of receptors (ER-), these drugs are generally not used.

Hormone receptor status – HER2+ = 15-20% of all breast cancers

HER2 (human epidermal growth factor receptor 2) is a protein that is found on the surface of all cells and controls how cells grow and divide.

Tumours that have high levels of these receptors are called HER2 positive (HER+). Tumours with low levels are called HER2 negative (HER2–).

It is often recommended that people with HER2+ breast cancer have chemotherapy and targeted therapy before they have surgery. This is known as neoadjuvant chemotherapy or neoadjuvant therapy.

You may also have chemotherapy or other therapy after surgery. This is known as adjuvant therapy.

Triple negative breast cancer – ER-, PR- and HER2- = 10-20% of all breast cancers

Some breast cancers are hormone receptor negative (ER– and PR–) as well as being HER2 negative (HER2–). These are called triple negative breast cancers.

Triple negative cancers do not respond to hormone therapy or to the targeted therapy drugs used for HER2+ cancers. The current treatment options for people with triple negative breast cancer include chemotherapy before and/or after surgery and some other types of targeted therapy drugs.

Triple negative breast cancers usually respond well to chemotherapy. Radiation therapy may also be given after some types of surgery. Women who have not been through menopause and people with a BRCA1 mutation are at higher risk of having triple negative breast cancer.

What are gene activity tests?

Known as molecular assays, genomic assays, or a gene expression profile, these tests look at which genes are active in the cancer cells. The patterns they show help to predict the risk of cancer returning. This can help guide treatment plans.

These tests may be suggested for some early breast cancers (ER+ and HER–) to see whether chemotherapy is needed. For example, if the risk of cancer returning is high, chemotherapy may be needed. If the risk is low, hormone therapy, or no extra therapy, may be suggested.

The current molecular assays used include Oncotype DX, EndoPredict, Prosigna and MammaPrint. They are not usually covered by Medicare or private health funds and can cost several thousand dollars.

Ask your medical oncologist if a gene activity test is of use for you. The standard pathology tests done on all breast cancers may be all that’s needed for your treatment plan.