Cancer Prevention: Who’s at Risk and When to get Screened

Doctor and patient reviewing X-ray

February 4 is World Cancer Day, though every day, millions of Canadians are impacted by the disease. The statistics are startling – two in five Canadians (44% of men and 43% of women) are expected to develop cancer in their lifetime, and one in four Canadians are expected to die from the disease.

Lung, breast, colorectal and prostate cancer are the most common cancers diagnosed in Canada, accounting for 46 percent of all new cases in 2021.

Though there is no sure-fire way to prevent cancer, regular screening in combination with a healthy lifestyle are some of the best steps you can take to stay healthy and cancer-free. For those who do develop cancer, early detection and treatment is key to improving health outcomes.   

“Regular cancer screening is imperative to catching the disease early and potentially saving your life,” said Dr. Naila Kassam, a primary care physician and Think Research’s Senior Medical Advisor. “It’s one of the best ways to detect cancer in its early stages when it’s much easier to treat.”

Below, we take a look at the most common cancers diagnosed in Canada, their symptoms and recommended screening guidelines.

Lung Cancer

An estimated 29,600 Canadians were diagnosed with lung cancer in 2021. Lung cancer occurs when cells in your lungs divide uncontrollably, causing tumours to grow. 

Common symptoms include incessant coughing that gets worse or doesn’t clear, chest pain, shortness of breath, and coughing up blood.

Smoking tobacco is a major risk factor for developing the disease, although not all diagnosed will have a history of smoking or exposure to secondhand smoke. Survival rates increase significantly when lung cancer is caught early.  

Who should be screened

Anyone presenting the above symptoms should talk to their doctor immediately. Otherwise adults aged 55 to 74 who currently smoke or have quit in the last 15 years should go through a risk assessment with their healthcare provider to see if they qualify for screening.

What’s involved

Low-dose computed tomography (CT) scan. This scan takes 3D X-rays of your lungs which are reviewed for the presence of cancer. 

Best prevention methods

Cigarette smoking is the leading cause of preventable lung cancer. If you don’t smoke, don’t start. If you do smoke, quit as soon as possible and avoid exposure to secondhand smoke. 

Cervical Cancer

An estimated 1450 Canadian women were diagnosed with cervical cancer in 2021. Cervical cancer occurs when cancer cells develop in the tissues of the cervix. Symptoms typically include irregular or heavy bleeding or bleeding after sexual activity.

Human papillomavirus (HPV) infections are a major risk factor for developing cervical cancer – you can get HPV by having sex with an infected person, though HPV is typically not harmful and infections often clear on their own.

Who should be screened

Women presenting any of the above symptoms should be screened immediately, otherwise women under 70 who are or who have been sexually active should undergo screening every three years starting at age 25, though provinces may differ in their recommended age of initiation.

What’s involved

A Pap smear (or Pap test). This process involves taking cells from the surface of the cervix and screening for abnormal or cancerous cells. Some women might experience mild discomfort during the procedure. 

Coming soon in Ontario: HPV testing. HPV testing is currently available through private pay in Ontario, however the province is working with the Ministry of Health to implement HPV testing in cervical screening.

Best prevention methods

Get the HPV vaccine. For maximum protection, people should get the vaccine before becoming sexually active, ideally, around age 11 or 12, however the Gardasil vaccine is safe for people ages 9-45.

Colon Cancer

An estimated 28,400 Canadians were diagnosed with colon cancer in 2021. Colon cancer occurs when cancerous cells form in the tissues of the colon. Symptoms typically include blood in the stool, a sudden but persistent change in bowel movements (e.g., diarrhea, constipation), and persistent stomach discomfort, including cramps or gas. When caught early, nine out of 10 people can be cured.

Who should be screened

Anyone presenting the above symptoms should be screened immediately with a colonoscopy, otherwise people aged 50-74 with average risk should be screened every two years with a FIT kit (more below). If you have a family history of colon cancer, you should start screening with a  colonoscopy at least 10 years before the age your relative was diagnosed.

What’s involved

Depending on your risk level, the following screening options are recommended.

Fecal immunochemical test (FIT): FIT tests are recommended for most people, including those at average risk (no immediate family history). A FIT test analyzes a stool sample for tiny amounts of blood which could be caused by colon cancer or abnormal growths. People with abnormal FIT tests should undergo a colonoscopy within eight weeks.

Flexible Sigmoidoscopy: A qualified healthcare professional uses a small, flexible tube outfitted with a camera to look inside the rectum and lower part of the colon. They can take tissue samples or remove polyps during the procedure. Though generally not painful, a flexible sigmoidoscopy can be mildly uncomfortable. 

Colonoscopy: Recommended for people at increased risk (those with a family history). A colonoscopy also uses a flexible tube outfitted with a camera, however it allows doctors to look at the entire colon. Many patients receive a mild sedative and/or painkillers prior to the procedure and should only experience mild discomfort.  

Best prevention methods

Though regular screening is the best prevention, regular exercise, and a healthy diet full of fruits, vegetables, and whole grains can help lower your risk.  

Breast Cancer

Approximately 27,700 Canadian women were diagnosed with breast cancer in 2021.Breast cancer occurs when cells in the breast grow and divide uncontrollably. There are several types of breast cancer, but the most diagnosed in Canada is ductal carcinoma, which begins when cancer cells grow in a milk duct.

Common symptoms of breast cancer include lumps on the breast or armpits, change in breast appearance, thickening or swelling on any part of the breast, irritation or dimpling of skin, and redness or flaky skin surrounding the nipple.

Risk factors for developing breast cancer are commonly linked to age (83 percent of breast cancers occur in women over 50), family history, obesity, and pregnancy history.

Breast cancer can also occur in men, though it accounts for less than one percent of diagnoses in Canada.

Who should be screened

Anyone with the above symptoms should be screened immediately, otherwise:

  • women aged 50-74 should have a mammogram every two years
  • women aged 30-69 at higher risk (family history, presence of the BRCA1 or BRCA 2 gene) should talk to their doctor for a referral into high risk breast cancer screening programs

What’s involved

A mammogram. This process involves taking an X-ray picture of the breasts to look for the presence of cancerous growth. Some women might experience mild discomfort during the procedure. 

Best prevention methods

There is no guaranteed way to prevent breast cancer, though a healthy diet and regular exercise can help lower your risk.

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The COVID-19 pandemic forced many healthcare services to pause, which has led to massive backlogs in cancer screenings. In Ontario alone, hundreds of thousands of patients missed routine screening appointments in 2021. 

If you missed a regular screening, contact your health provider as soon as possible to schedule an appointment. 

“Remember, cancer won’t wait for the COVID-19 pandemic to subside,” said Dr. Kassam. “It’s important to stay on track with your cancer screenings. Contact your healthcare provider as soon as you can to schedule an appointment.”