Breast cancer

In this section we talk about about early and locally advanced breast cancer.

Learn more about:

• What is breast cancer?
• The breasts
• Who gets breast cancer?
• What are the different types of breast conditions?
• What causes breast cancer?
• How common is breast cancer

What is breast cancer?

Breast cancer is the abnormal growth of the cells lining the breast ducts or lobules. These abnormal cells have the potential to spread to other parts of the body.

Most breast cancers are found when they are invasive. This means 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).

The breasts

Everyone has breast tissue.

Female breasts are mostly made up of:

• lobes – each breast is divided into 12–20 sections called lobes
• lobules – each lobe contains glands that can produce milk; these milk glands are called lobules or glandular tissue
• ducts – the lobes and lobules are connected by fine tubes called ducts; the ducts carry milk to the nipples.

Male breast tissue has ducts but few or no lobes and lobules.

All breasts also contain fibrous and fatty tissue. Some breast tissue extends into the armpit (axilla).

Most younger females have dense breasts, because they have more glandular tissue than fat in them.

The breasts (diagram)

The lymphatic system

The lymphatic system is an important part of the immune system. It protects the body against disease and infection. It is made up of a network of thin tubes called lymph vessels that are found throughout the body. Lymph vessels connect to groups of small, bean-shaped structures called lymph nodes or glands.

Lymph nodes are found throughout the body, including in the armpits, neck, abdomen and groin, and behind the breastbone (sternum). The lymph nodes in the armpit (axillary lymph nodes) are often the first place cancer cells spread to outside the breast.

Who gets breast cancer?

Anyone can develop breast cancer. While it is much more common in women, men can also get breast cancer. Breast cancer in males is usually diagnosed and treated in the same way as it is for females.

For more information for men diagnosed with breast cancer, visit breastcancerinmen.canceraustralia.gov.au or download BCNA’s Men get breast cancer too booklet.

Transgender and gender-diverse people can also get breast cancer.

A transgender woman who is taking medicines to boost female hormones and lower male hormones may have an increased risk of developing breast cancer.

A transgender man who has a mastectomy is still at risk of developing breast cancer. This is likely due to small amount of breast tissue that may remain after surgery.

What are the different types of breast conditions?

Non-invasive breast conditions

Also called carcinoma in situ. These are a precancerous condition where the cells look like cancer cells, but have not invaded nearby tissues.

Invasive breast cancer

There are two main types of invasive breast cancer. They are named after the area of the breast they start in.

Less common types of breast cancer

These include inflammatory breast cancer, Paget’s disease of the nipple, medullary carcinoma, mucinous carcinoma and papillary carcinoma.

Advanced or metastatic breast cancer

If invasive breast cancer spreads beyond the breast tissue and nearby lymph nodes, it is called advanced or metastatic breast cancer.

For more information on less common types of breast conditions or advanced breast cancer, call Cancer Council 13 11 20, or visit Breast Cancer Network Australia or Cancer Australia.

What causes breast cancer?

Many factors can increase your risk of breast cancer. But having risk factors does not mean that you will develop breast cancer. For more on this, see Cancer Australia’s Breast Cancer Risk Factors or petermac.org/iprevent.

Female specific

Male specific

How common is breast cancer?

Breast cancer is the most common cancer in Australian women (apart from common skin cancers). About 17,000 women are diagnosed with breast cancer each year, and one in eight will be diagnosed by the age of 85.

Although breast cancer can occur at any age, it is more common in women over 40. Almost 70% of breast cancers are diagnosed in women aged 40–69, and about 25% are diagnosed in women aged 70 and over. In rare cases, women are diagnosed during pregnancy. About 150 men are diagnosed with breast cancer in Australia each year, and most of these men are over 50.