Breast cancer occurs when abnormal cells in the breast grow in an uncontrolled way and can start in the ducts or the lobules (milk sacks) of the breast. Cancer that remains in the ducts or lobules is called non-invasive breast cancer. If the cancer spreads, it becomes invasive cancer.

Breast cancer is not sex-specific but is far more common in people assigned female at birth. It is estimated that in 2022, 20,640 new cases of breast cancer were diagnosed (including 212 diagnoses in people assigned male at birth), making it the most commonly diagnosed cancer in Australia.

Factors that increase the risk of breast cancer include increasing age, family history, inheritance of mutations in the genes BRCA2, BRCA1 and CHEK2, and/or a menstrual cycle that began before the age of 12.

Ductal carcinoma is the most common type of breast cancer. This type of cancer forms in the lining of a milk duct within your breast. Ductal carcinoma can remain within the ducts (ductal carcinoma in situ), or it can break out of the ducts (invasive ductal carcinoma)

Lobular carcinoma in situ (LCIS) is a non-invasive breast cancer that stays within the lobules of the breast, where breast milk is produced. When it breaks out of the lobules, it's considered invasive lobular carcinoma. The lobules are connected to the ducts, which carry breast milk to the nipple.

Metastatic breast cancer (also called advanced breast cancer) is an invasive breast cancer that has spread from the breast to other parts of the body.

• A lump or the sensation of lumpiness
• A change in size or shape of the breast
• Any changes to the nipple, including crusting, redness, inversion, or discharge
• Redness or dimpling of the skin on the breast
• Persistent pain in or around the breast 

It is important to note that you should regularly check your breasts as part of your daily routine, whether it's while getting dressed or during your shower, so you notice any changes if they happen. Find more information here. 

If you have any signs and symptoms, please see your GP. They will first perform a physical examination to check for any visible irregularities in your breasts. They may also ask about your medical history and any family history of breast cancer.

If necessary, the GP can then refer you for a mammogram, which may be followed by an ultrasound.

If breast cancer is suspected, some of the breast tissue will be removed and sent to a lab for examination. If cancer is detected, you may have additional scans to see if the cancer has spread to other parts of your body.

Breast cancer screening is a vital, life-saving tool for detecting breast cancer at an early stage, when there are no signs or symptoms. The screening involves a mammogram, a type of low-dose x-ray that can detect changes which may be too small to be felt during a physical examination. 

BreastScreen Australia is the national breast cancer screening program, which is available in each state and territory.

People assigned female at birth who are aged between 50-74 and have no breast cancer symptoms are encouraged to participate in a free breast cancer screening every 2 years. This is because the biggest risk factors for developing breast cancer are being assigned female at birth and increasing age. 

People assigned female at birth aged between 40-49 years and aged 75 and over who have no breast cancer symptoms are also eligible for a free breast cancer screening every 2 years. 

For more information, you can head to the BreastScreen Australia website or you can call them on 13 20 50.

Breast cancer is usually graded in stages from 1-4. Early breast cancer is stage 1 or 2. The cancer is contained in the breast and may or may not have spread to lymph nodes in the armpit.

Locally advanced breast cancer is stage 3. The cancer is larger than 5 cm, has spread to tissues around the breast, or has spread to a large number of lymph nodes.

Metastatic breast cancer  is stage 4. This means breast cancer has spread to other parts of the body. It is also called secondary or advanced breast cancer.

A prognosis will depend on the stage and grade of the cancer. The lower the grade, the better the prognosis. The survival rate for people with breast cancer has increased significantly over time as a direct result of research. Breast cancer now has one of the highest five-year survival rates when diagnosed early.