Breast Cancer: What you need to know

| Health and Wellness

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Understanding Breast Cancer

Chances are you know someone whose life has been touched by breast cancer. In Canada, it’s the most common type of cancer in women: one in eight will develop breast cancer, and one in 31 will die of the disease. (Breast cancer is rare in men, but it does happen, accounting for less than one percent of cases.)

Advancements in research, screening and treatment have improved survival rates over the past 30 years, but breast cancer remains a life-altering disease with serious physical and emotional effects.

Like other types of cancer, breast cancer is caused by abnormal cells that grow uncontrollably, forming a tumour. The growth is malignant (cancerous) if it spreads to other parts of the body. (Not all abnormal growths are cancer; there are also benign conditions that affect the breasts.)

Cancer can start in different parts of the breast. The most common areas are the milk ducts (ductal carcinoma) or the lobules, the milk-producing glands (lobular carcinoma). A person’s prognosis (health outcome) depends on factors such as the cancer’s size and type. Age is also a factor – women under 35 are at greater risk of recurrence and tend to have more aggressive, higher-grade cancer than post-menopausal women.

Risk factors

A woman’s chances of developing breast cancer depends on her unique combination of internal and external risk factors. The Canadian Cancer Society lists several known risk factors:

  • Prior diagnosis of breast cancer
  • Family history of breast cancer and other types of cancer
  • Mutations to breast cancer gene 1 (BRCA1) or breast cancer gene 2 (BRCA2); these genes normally suppress tumour growth (mutations are rare, affecting one in 500 people)
  • Ashkenazi Jewish ancestry (BRCA1 and BRCA2 mutations affect one in 40 Ashkenazi Jewish women)
  • Dense breast tissue, which is an inherited trait
  • Reproductive history: breast cancer risk is higher for women who had their first period early (age 11 or younger) or entered menopause late (age 55 or older), or who had their first full-term pregnancy after age 30 or who have never been pregnant
  • Rare genetic conditions, including specific gene mutations
  • Exposure to ionizing radiation (for example, radiation therapy for Hodgkin lymphoma)
  • Taking oral contraceptives containing estrogen and progesterone for 10 years or more (this risk decreases if medication is discontinued)
  • Taking hormone replacement therapy (HRT) for five years or more
  • Atypical hyperplasia – an increase of abnormal cells in breast tissue; this is a benign condition, but it increases breast cancer risk
  • Alcohol consumption, even at low levels (a little more than one drink per day)
  • Obesity, which increases breast cancer risk in post-menopausal women
  • Tall adult height, which is indicative of two factors that increase risk: a person’s energy intake and diet early in life
  • High socio-economic status, which tends to be associated with having fewer children and/or having children later in life – both linked to increased breast cancer risk

Possible risk factors include physical inactivity, adult weight gain, higher weight at birth, smoking (including exposure to second-hand smoke) and working night shifts (which affects the amount of melatonin in the body).

To reduce your risk, the Canadian Cancer Society recommends maintaining a healthy body weight, limiting alcohol consumption, avoiding smoking and following its screening guidelines:

  • Age 40 to 49: Talk to your doctor about your risk of breast cancer, along with the benefits and risks of mammography.
  • Age 50 to 74: Have a mammogram every two to three years.
  • Age 74 or older: Talk to your doctor about how often you should have a mammogram.

Signs and symptoms

These signs and symptoms don’t necessarily indicate cancer, but it’s best to consult your doctor. Early cancer detection increases the success of treatment.

  • Lump in the breast that doesn’t shrink or disappear during your menstrual cycle. It might feel like it’s attached to the skin or chest wall. The lump may be hard or tender.
  • Lump in the armpit
  • A change in the size or shape of the breast
  • Dimpling, puckering or thickening of the skin of the breast
  • Redness, swelling and increased warmth in the breast
  • Changes to the nipple (for example, non-inverted nipples become inverted, nipple has unusual discharge, or nipple has scaling, crusting or ulcers)
  • Itchy nipple or breast

Late signs and symptoms that may indicate that cancer has spread include nausea, bone pain, loss of appetite, jaundice, weight loss, headache, double vision and muscle weakness. If you experience unusual symptoms, see your doctor.

Diagnosing breast cancer

Tests for breast cancer diagnosis and staging (determining whether the cancer has spread) include physical examination, mammography, ultrasound and other imaging tests. A breast biopsy, in which a small amount of tissue is removed and checked for cancerous cells, is the only definite way to diagnose cancer. Additional tests (such as blood tests, lymph node biopsy, bone scans and chest X-rays) help determine the cancer’s stage.

Treating breast cancer

People who have cancer are treated by an oncologist, a physician who specializes in cancer. The treatment plan depends on the type of breast cancer, its stage (tumour size, and whether it has spread) and its grade (how the cells look and behave – for example, how quickly the tumour is growing). Oncologists also consider a woman’s age, overall health and personal decisions about treatment.

Treatment plans also depend on the cancer’s hormone receptor status (whether the female hormones estrogen and progesterone can attach to its cells; this helps determine whether or not to use hormonal therapy), and the cancer’s HER2 status (HER2 is a gene that can influence a tumour’s growth; HER2-positive cancers are more aggressive).

Treatment may include surgery, radiation therapy, hormone therapy, chemotherapy, hormonal therapy or biological therapy.

Life after breast cancer

After treatment, people continue regular medical check-ups and cancer screening. A wellness plan, developed with health professionals, can help people regain strength, cope with stress and side effects, and lower their risk of cancer recurrence.

Meeting others who have experienced cancer can be tremendously helpful. To find peer and family support groups, contact your local Canadian Cancer Society office or join the organization’s online community, Professional counselling can also help people cope.


Canadian Cancer Society
Cancer Care Ontario
Canadian Breast Cancer Foundation