Breast cancer


Breast cancer overview

Page last updated: October 2024

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What is breast cancer?


Breast cancer is the abnormal growth of cells in the breast. It usually starts in the lining of the breast ducts or lobules, and can grow into cancerous (malignant) tumours.

Most breast cancers are found when they are invasive. This means that the cancer has spread from the breast ducts or lobules into the surrounding breast tissue.

Invasive breast cancer can be early, locally advanced or advanced (metastatic). Advanced breast cancer is when cancer cells have spread (metastasised) outside the breast and nearby lymph nodes to other parts of the body.

About 5% of cancers are advanced when breast cancer is first diagnosed.

This information has been prepared to help you understand more about early and locally advanced breast cancer, and includes a short section on advanced (metastatic) breast cancer.

The breasts

The lymphatic system

 

Your guide to best cancer care

A lot can happen in a hurry when you’re diagnosed with cancer. The  guide to best cancer care for breast cancer can help you make sense of what should happen.

It will help you with what questions to ask your health professionals to make sure you receive the best care at every step.

Read the guide

Types of breast conditions

Non-invasive breast conditions

Invasive breast conditions

How common is breast cancer?

There are about 20,000 people diagnosed with breast cancer in Australia every year.

Women

Men

Transgender, non-binary and gender-diverse people

Learn more

Risk factors

Many factors can increase your risk of breast cancer, but they do not mean that you will definitely develop it. You can also have none of the known risk factors and still get breast cancer. If you are worried, speak to your doctor. 

Personal factors

Lifestyle factors

Family history

Hormonal factors

Medical history

Reproductive factors

 

Does breast cancer run in families?

Most people with breast cancer don’t have a family history, but a small number may have inherited a gene fault (also called a mutation) that increases their breast cancer risk.

  • BRCA1 and BRCA2 – these are the most common gene mutations linked to breast cancer. Women in families with BRCA1 or BRCA2 are at increased risk of breast and ovarian cancers. Men in families with BRCA2 may be at increased risk of breast and prostate cancers.
  • Other genes linked to breast cancer – these include ATM, BARD1, CDH1, CHEK2, PALB2, PTEN, RAD51C, RAD51D, and TP53. More gene mutations linked to breast cancer are being found all the time. A genetic test called an extended gene panel test checks for the most common types of genes linked with breast cancer.

To find out if you have inherited a gene mutation, talk to your doctor or breast cancer nurse about visiting a family cancer clinic or genetic oncologist. Your specialist may also be able to order genetic tests.

In particular, women diagnosed before 40 years, those with triple negative breast cancer diagnosed before 60 years, and men with breast cancer should ask for a referral.

Genetic testing is covered by Medicare for some, but not all, people; ask your doctor about this.

Learn more

Symptoms

Breast cancer sometimes has no symptoms, so regular checks are important for women aged 40 and over. Breast changes may not mean cancer, but see a doctor if you notice:

  • a lump, lumpiness or thickening, especially in just one breast
  • a change in the size or shape of the breast or swelling
  • a change to the nipple – change in shape, crusting, sores or ulcers, redness, pain, a clear or bloody discharge, or a nipple that turns in (inverted nipple) when it used to stick out
  • a change in the skin – dimpling or indentation, a rash or itchiness, scaly appearance, unusual redness or other colour changes
  • swelling or discomfort in the armpit or near the collarbone
  • ongoing, unusual breast pain not related to your period.

Health professionals

You may be sent for tests after a screening mammogram, or your general practitioner (GP) may arrange tests to check your symptoms. If these tests do not rule out cancer, you will usually be referred to a specialist or breast clinic.

If breast cancer is diagnosed, you will see a breast surgeon or a medical oncologist, who will talk to you about your treatment options. Often these will be discussed with other health professionals at a multidisciplinary team (MDT) meeting.

During and after treatment, you will see a range of health professionals who specialise in different aspects of your care. You may not see all members of the MDT.

Question checklist

 

Understanding Breast Cancer

Download our Understanding Breast Cancer booklet to learn more

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