Download Module 1 Student Activity Fact Sheet 1

MODULE 1
UNDERSTANDING
BREAST CANCER
Fact Sheet 1: What is breast cancer?
What is breast cancer?
Breast cancer occurs when cells in the breast grow in an uncontrolled way. Normally,
cells grow and multiply in an orderly way, but changed genes can cause them to behave
abnormally.
Breast cancer symptoms
Breast cancer can have many different symptoms. If any new changes are detected
people should see a doctor:
 new lump or lumpiness, especially if it's only in one breast
 change in the size or shape of the breast
 change to the nipple, such as crusting, ulcer, redness or inversion
 nipple discharge that occurs without squeezing
 change in the skin of the breast such as redness or dimpling
 unusual pain that doesn't go away
Note: Nine out of ten breast changes aren't due to cancer, but it’s important to see a
doctor to be sure.
Most breast lumps are benign (non cancerous), harmless and do not spread to other
parts of the body.

Malignant breast lumps are made up of cancer cells. When it first develops, this
malignant tumour is confined to the breast.

In young people, around 99 per cent of breast lumps are benign and almost all
lumps in high school aged girls are normal.
Where breast cancer develops
Breast cancer develops in either the ducts or the lobules. Lobules are where the milk is
produced, and ducts are where the milk travels to the nipple when a woman is
breastfeeding.
Cancer cells develop when the cells lining the ducts or the lobules become abnormal in
size and shape and start multiplying in an uncontrollable way.
If the cancer is not removed and controlled, the cancer cells can spread to other parts of
the body. This is called secondary cancer, advanced cancer or metastases.
What causes breast cancer?
Although there are a number of factors that may increase someone’s risk of developing
breast cancer, no one knows what actually causes it.
© Breast Cancer Care WA 2010
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