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Breast cancer

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Malignant tumours of the breast

Malignant tumours of the breast are cancerous growths that have the potential to spread (metastasize) to other parts of the body.


The most common type of malignant breast tumour is adenocarcinoma. Nearly all breast cancers start in the glandular tissue in the breast, in either the milk ducts or the milk glands. Most adenocarcinomas occur in the upper, outer part of the breast.

There are 2 main types of adenocarcinoma:

  • ductal carcinoma – begins in the lining of the milk ducts of the breast
  • lobular carcinoma – begins in the milk glands (lobules) of the breast

Ductal carcinoma and lobular carcinoma are also classified according to whether they are:

Other types of malignant breast tumours

There are other less common types of malignant breast tumours:


Dr Marc Therrien Dr Marc Therrien is working toward blocking a cancer-driving protein.

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Clinical trial discovery improves quality of life

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A clinical trial led by the Society’s NCIC Clinical Trials group found that men with prostate cancer who are treated with intermittent courses of hormone therapy live as long as those receiving continuous therapy.

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