Health A to Z

Breast cancer

Increase your knowledge of the most diagnosed cancer among Canadian women with this overview.

Breast cancer is cancer within the breast glands or ducts. It is the most frequently diagnosed cancer among Canadian women, with one in nine expected to develop the disease in her lifetime. More than 400 Canadian women are diagnosed with breast cancer each week and in 2010, an estimated 5,300 Canadian women will die from the disease. More than 50 percent of breast cancers will be diagnosed in women between ages 50 and 69.

Breast cancer causes The exact causes of breast cancer are unknown; however, experts believe that a combination of hereditary and environmental causes result in the cell DNA changes that lead to breast cancer.

Breast cancer symptoms Typically the first sign of breast cancer is a painless lump in the breast or armpit. Other symptoms include changes in breast size or shape; thickening or dimpling of the skin; redness, swelling or warmth in the affected breast; crusting or scaling on the nipple or an inverted nipple.  Other conditions can cause these symptoms — they are often not caused by cancer — so testing is necessary for a diagnosis.

Breast cancer diagnosis/tests If you find a lump in your breast or your doctor does during a clinical breast exam, she’ll send you for tests to see if it’s cancer, such as a mammogram, an X-ray of the breast used to screen for breast cancer. You may also get a requisition for a breast ultrasound, which can help deduce if a lump is merely a cyst or a tumour. Breast magnetic resonance imaging (MRI), is another breast test, which involves getting a dye injection so the MRI machine can create pictures of the inside of your breasts. In some cases you’ll be referred to a surgeon for a biopsy, where a sample of breast cells are removed and sent to a lab for testing.

Breast cancer treatmentIt depends on the size of the tumour and type and stage of the breast cancer. Often two or more methods are used together.

Surgery may be performed to remove the cancer, either a lumpectomy to remove the cancerous part of the breast and a small amount of surrounding tissue, or a mastectomy to remove the entire breast and some underarm lymph nodes.

Radiation therapy is usually administered after surgery to destroy cancer cells.

Chemotherapy treats the cancer with medication, which interferes with the ability of the cancer cells to grow and spread.

Hormone therapy may be an effective treatment for estrogen receptor-positive breast cancer, in which the presence of estrogen can promote cancer cell growth. Hormone therapy removes hormones from your body, or interferes with the way they work, in order to stop cancer cells from growing.

HER-2 therapy is effective for sufferers whose cancer cells have more than the usual number of HER-2 receptors, which are believed to be involved in cell growth. HER-2 therapy involves medication, called trastuzumab or Herceptin, that disrupts the growth of HER-2-positive cancers cells, resulting in slower growth of the cancer.

Breast cancer prevention You can’t change your age or your gene pool but it may be possible to reduce your risk for breast cancer.

Diet Obesity has been linked to breast cancer so eat a healthy diet that’s low in fat and get regular exercise which will help you maintain a healthy weight.  There is growing evidence that vitamin D may lower the risk for breast cancer so get enough by spending time outside in the sun, through your diet and supplements. Stick to one alcoholic drink or less a day, since there’s a link between alcohol consumption and the disease.

Detection  Since early detection is important, get to know your breasts by looking at and feeling them so you know when something feels wrong.  See your doctor immediately if you notice any changes. You may want to consider genetic screening if breast cancer runs in your family.

Chemicals The oral contraceptive pill slightly increases the risk of breast and other cancers and HRT (hormone replacement therapy) for menopause may also increase your risk; talk to your doctor about the risks in your case.

Environment The Canadian Cancer Society has concerns about long-term exposure to phthalates, a group of chemicals in plastics and cosmetics; avoid them.

More info from Chatelaine
Know your breasts
Breast Friends: Celebrating stories of friendship and courage
How to support a friend with breast cancer
30 breast facts
Think pink and shop for the cause
Blog: Living with Breast Cancer
Breast cancer lingo A-H
Your breast cancer guide
The latest treatments

Outside resources
Canadian Breast Cancer Foundation
Breast Cancer Society of Canada
Rethink Breast Cancer