Cancerous tumours of the breast
A cancerous tumour of the breast can grow into and destroy nearby tissue. It can also spread (metastasize) to other parts of the body. Cancerous tumours are also called malignant tumours.
Ductal carcinoma and lobular carcinoma
Nearly all breast cancers are adenocarcinomas. These tumours start in gland cells. The most common adenocarcinomas of the breast are:
- ductal carcinoma (including ductal carcinoma in situ, or DCIS), which starts in the milk ducts
- lobular carcinoma, which starts in the groups of glands that make milk (called lobules)
Doctors will classify these tumours as non-invasive or invasive. Non-invasive means that the cancer cells have not spread beyond the duct or gland where they started. Invasive means that the cancer cells have started to spread into the surrounding tissue.
Other types of breast cancer
The following types of cancer can also develop in the breast:
- inflammatory breast cancer
- Paget disease of the nipple
- triple negative breast cancer
Rare breast tumours
The following cancerous tumours of the breast make up less than 1% of all breast cancers:
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What’s the lifetime risk of getting cancer?
The latest Canadian Cancer Statistics report shows about half of Canadians are expected to be diagnosed with cancer in their lifetime.