Breast Cancer

Breast cancer is a disease that occurs when cells in the breast grow out of control.

Essential Information

There are different kinds of breast cancer as it can begin in different parts of the breast. Most breast cancers begin in the ducts (which carry milk to the nipple) or lobules (the glands that make milk). Breast cancer can spread outside the breast through blood vessels and lymph vessels. When breast cancer spreads to other parts of the body, it is said to have metastasized.

While breast cancer occurs most of the time in women, men can get breast cancer, too.

  • Breast cancer occurs when cells in the breast grow out of control
  • Breast cancer can be found in different parts of the breast
  • Tests and procedures used to diagnose breast cancer include a breast exam, mammogram, breast ultrasound, biopsy and breast magnetic resonance imaging (MRI)
  • Treatment plans are customized per patient, but could include surgery, chemotherapy and radiation

The most common kinds of breast cancer are:

  • Invasive ductal carcinoma: The cancer cells grow outside the ducts into other parts of the breast tissue. Invasive cancer cells can also spread, or metastasize, to other parts of the body.
  • Invasive lobular carcinoma: Cancer cells spread from the lobules to the breast tissues that are close by. These invasive cancer cells can also spread to other parts of the body.

There are several other less common kinds of breast cancer: Paget’s disease, external medullary, mucinous, and inflammatory breast cancer.

Ductal carcinoma in situ (DCIS) is a breast disease that may lead to breast cancer. The cancer cells are only in the lining of the ducts, and have not spread to other tissues in the breast.

Tests and procedures used to diagnose breast cancer include:

  • Breast exam: Your doctor will check both of your breasts and lymph nodes in and around your armpit, feeling for any lumps or other abnormalities. Breast cancer cells usually form a tumour that can often be seen on an X-ray or felt as a lump.
  • Mammogram: An X-ray of the breast.
  • Breast ultrasound: Uses sound waves to produce images of structures deep within the body.
  • Biopsy: An important test in determining a diagnosis of breast cancer. Biopsy samples are sent to a laboratory for analysis where experts call pathologists determine whether the cells are cancerous.
  • Breast magnetic resonance imaging (MRI): A machine that uses a magnet and radio waves to create pictures of the interior of your breast.

Other tests and procedures may be used depending on your situation.

  • Surgery: Most women with breast cancer will have surgery as a part of their breast cancer treatment. Learn more about our breast surgical services.
  • Medical oncology:The branch of medicine that treats cancer with drugs that affect the whole body is also called “systemic” therapies because they affect the entire body system.
  • Radiation therapy: It is typically part of the treatment plan after breast-conserving surgery. In some cases, it may also be given after a mastectomy. It is also used to treat breast cancer that has spread to the bones, lungs or brain.
  • Hormonal therapy: Often used to treat hormone receptor-positive breast cancer. Post-menopausal women are given different hormonal therapy drugs than premenopausal women.
  • Targeted therapy: May be given alone or in combination with chemotherapy, hormonal therapy or both.

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