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HealthInfo Waitaha Canterbury

Overview of breast cancer

Mō te ūtaetae

This page has links to information in te reo Māori.


breast anatomyBreast cancer is a cancer that grows in your breast tissue.

Your breasts are made up of different types of tissue, including lobules (which hold your milk-producing glands), ducts (which carry the milk to the nipple), fatty tissue, blood vessels, lymph vessels and nerves.

Breast cancer is the most common cancer in New Zealand women – around 3,000 are diagnosed each year. It mostly affects women aged over 50, but it can also happen in young women, so it's important to get to know your own breasts and be breast aware from the age of 20.

Men can also get breast cancer, but this is very rare – only around 20 New Zealand men a year are diagnosed with breast cancer.

Symptoms of breast cancer

The most common symptom of breast cancer is a painless lump or thickening in your breast.

Breast lumps are relatively common and most aren't cancer. But if you find a lump in your breast, it's best to see your general practice team so they can assess it and arrange any investigations you might need.

Other symptoms that may be a sign of breast cancer include:

Breast pain is not usually a sign of breast cancer.

Diagnosing breast cancer

Breast cancer is usually found either through a screening mammogram or diagnostic breast imaging that is done after a woman notices changes in her breast.

A screening mammogram can pick up breast cancer before you even notice any symptoms.

Initially, diagnostic breast imaging is similar to a screening mammogram, but then it focuses on any abnormal areas that you've found. Your general practice team may refer you for one if you find a lump or change in your breast. You can have diagnostic breast imaging at any time, even if you've had a clear screening mammogram within the past two years.

Women younger than 35 may have an ultrasound first rather than a mammogram. This is because younger women have denser breast tissue, and an ultrasound can give a clearer picture. If the first mammogram or ultrasound shows any unusual-looking areas, you may be recalled to have another image taken.

Further tests you might need

If you need further investigation, you may need a biopsy, which is a sample of the area of concern taken to look at under a microscope to find out whether it's cancer, possibly cancer or non-cancerous (benign).

Treating breast cancer

If you have breast cancer, the treatment offered depends on the type and stage of the cancer. Read more about it here.

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On the next page: Reducing your risk of breast cancer

Written by HealthInfo clinical advisers. Last reviewed September 2022.


Page reference: 393199

Review key: HIBCA-57360