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Colorectal Cancer

The large bowel is part of the digestive system, and consists of the colon and rectum. The colon soaks up extra water from your stool (poop) and the rectum pushes stool out of the body.

Colon cancer can form in any part of the colon, which is the lower part of the digestive system. Rectal cancer can form in the rectum, which is the last 15 centimeters of the large bowel. Together they are often called “colorectal cancer” or “bowel cancer”. There are different treatments for colon cancer and rectal cancer.

Colorectal cancer and polyps (small growths) start in the cells lining the inside of the colon or rectum. Some polyps can turn into cancer over time. These polyps are called “pre-cancerous polyps.”

To learn more about colorectal cancer, visit the Canadian Cancer Society.

What is on this Page

You will find Ontario Health (Cancer Care Ontario) information, resources and tools for:

  • screening participants, people with cancer, families and caregivers
  • anyone interested in colorectal cancer
  • healthcare providers

You will also find links to other organizations that have information on colorectal cancer.


There are several things you can do to lower your risk of colorectal cancer:

Limit the Amount of Alcohol You Drink

People who regularly drink 25 grams (or about 2 standard drinks) of alcohol a day have a 20% increased risk of getting colorectal cancer.

People who drink heavily also may not eat a healthy diet. As a result, they may lack nutrients like vitamin D, calcium and folate that appear to help protect against colorectal cancer.

Do Not Smoke

Smoking is linked to many types of cancer and other diseases. There is no safe kind of tobacco product and no safe amount of smoking.

It’s never too late to benefit from becoming smoke-free. If you are already a non-smoker, keep yourself safe by avoiding exposure to other people’s tobacco smoke (second-hand smoke).

It may take several tries to quit smoking. If you’ve tried to quit in the past and have started smoking again, don’t give up. Each time you try to quit, you get closer to your goal of being smoke-free forever.

To find information on how to quit smoking visit:

Limit the Amount of Red and Processed Meats You Eat

Eating 100 grams of red meat (about the size of a deck of cards) or 50 grams of processed meat a day raises your risk of colorectal cancer by up to 20%.

Eat Foods High in Fibre

A high-fibre diet may help lower your risk of colorectal cancer. Fibre helps keep the colon healthy by speeding up the removal of stool (poop).

You can get fibre from whole grains, vegetables and some fruit. Vegetables and fruit can also help:

  • prevent nutritional deficiencies
  • provide you with natural sources of cancer-fighting vitamins
  • help you reach or stay at a healthy weight

Maintain a Healthy Weight

If you’re not at a healthy weight, losing even a small amount of weight can help lower the risk to your health. Small changes in your diet and physical activity may be enough to help you become healthier.

Stay Active

Being physically active can increase your health, well-being and quality of life, and reduce your risk of cancer. Being “active” doesn’t mean just formal exercise programs — lots of everyday activities, such as gardening, housework, dancing, or walking to work or the store, also count. Many are activities you can do with family or friends.

Check if You Are at High Risk

There are risks you inherit from your family. The genes you are born with and whether or not your family members have had cancer both play a part in your risk of getting cancer. Genetic testing can tell if you have genetic changes (mutations) that increase your risk of certain cancers, like colorectal cancer.

Although they are relatively rare, some genetic conditions are strongly related to colorectal cancer. They include:

  • familial adenomatous polyposis (FAP) and attenuated FAP
  • MYH-associated polyposis (MAP)
  • Peutz-Jeghers syndrome
  • Lynch syndrome
  • juvenile polyposis

Ontario’s colorectal cancer screening program, ColonCancerCheck, does not screen people who are at high risk of colorectal cancer because of genetic conditions. The program focuses on screening people at average or increased risk.

    Talk with your doctor or nurse practitioner to see if you would benefit from genetic assessment.

    For more details on genetic testing, visit the Canadian Cancer Society.


    Cancer screening is testing done on people who are at risk of getting cancer, but who have no symptoms and generally feel fine.

    Research shows that almost 7 out of 10 people diagnosed with colorectal cancer have no family history of the disease. This means it is important to get screened for colorectal cancer, even if you do not have a family history of the disease. Research also shows that most people who have been diagnosed with the disease are older than age 50. This is why most people should start screening for colorectal cancer at age 50.

    Getting screened helps find colorectal cancer early, when it is more likely to be cured. When colorectal cancer is caught early, 9 out of 10 people with the disease can be cured. If someone does not get screened, they could have colorectal cancer and not know it.

    The kind of screening test you get depends on whether you are at average risk of getting colorectal cancer or at increased risk for getting colorectal cancer.

    For People at Average Risk

    Someone is at average risk if they are 50 to 74 years old with no first-degree relative (parent, sibling or child) who has been diagnosed with colorectal cancer.

    If you are at average risk of getting colorectal cancer:

    • you should get screened once every 2 years with the fecal immunochemical test (FIT)
    • you may also choose to get screened with flexible sigmoidoscopy (a different colorectal cancer screening test) every 10 years instead of FIT

    For People at Increased Risk

    Someone is at increased risk if they have a family history of colorectal cancer that includes 1 or more first-degree relatives (parent, sibling or child) with the disease.

    If you are at increased risk of getting colorectal cancer, you should get screened with colonoscopy (a different colorectal cancer screening test) starting at age 50, or 10 years earlier than the age your relative was diagnosed, whichever comes first.

    Some Tests are not Recommended

    You may hear about other colorectal cancer screening tests, but Ontario’s colorectal cancer screening program, ColonCancerCheck, does not recommend using them.

    For more information see the “Types of Screening” section on the Screening for Colorectal Cancer page.

    Learn More

    Go to the Screening for Colorectal Cancer page to learn more about:

    • different types of screening tests
    • when and where to get screened for colorectal cancer
    • why some tests are not recommended for screening


    During diagnosis, a person may need many tests to confirm the cancer. Waiting for test results to come back can be stressful. If you are waiting for a diagnosis, talk to your doctor or nurse practitioner about managing stress during this difficult time.

    For more information about diagnostic tests for colorectal cancer, visit the Canadian Cancer Society.

    Starting the Diagnostic Process

    Not everyone follows the same diagnostic process. Some people may be helped through the process by their family doctor, while others may be helped by a specialist or a Diagnostic Assessment Program (DAP).

    In many cases, a family doctor is the first contact point in the process of diagnosing cancer and is the one to refer a patient to a specialist or DAP.

    To check if a DAP is available in your area, go to our map of DAP locations.


    Treatment for colorectal cancer will depend on:

    • the type of cancer
    • the stage of cancer
    • which treatments the person chooses to have

    Treatments may include:

    • surgery
    • drug therapy (chemotherapy)
    • radiation therapy
    • other treatment options
    • clinical drug trials

    To learn more about types of colorectal cancer treatment, visit the Canadian Cancer Society.

    Drug Therapy Information

    You can learn more about specific cancer drugs using our patient information sheets. These provide information about cancer drug therapies, including what they are used for and how to manage side effects. To find patient information sheets, go to the Drugs page.

    You can also see About Chemotherapy for general information about cancer drug therapy.

    Quitting Smoking Can Help Your Treatment

    It’s never too late to quit smoking. Whether you are scheduled to have surgery, radiation treatment or chemotherapy, quitting smoking can help your treatment work better. It also can reduce the chance of your cancer coming back or getting another form of cancer. For more information and resources, see Benefits of Quitting Smoking for People with Cancer.

    Managing Symptoms and Side Effects

    People with cancer may have symptoms related to their cancer or as a side effect of treatment.

    Our symptom management guides explain:

    • how to recognize symptoms
    • what to do and what not to do
    • when to contact the person’s healthcare team

    The guides are available for patients and for healthcare providers. Each patient guide also comes with links to helpful resources like courses, books, videos and worksheets.

    Our side effect information sheets offer tips for people who have side effects from chemotherapy treatment.

    If you are a person with cancer, please remember that it’s important to discuss any symptoms or concerns with your healthcare team.

    Clinical Trials

    Clinical trials are scientific studies that test the safety and effectiveness of a medical treatment. Find clinical trials in Canada.

    Palliative Care

    Palliative care supports people with life-threatening illness and their families. The goal of this care is to relieve suffering so people can have the best possible quality of life. Palliative care should start when a person is diagnosed with a serious illness.

    To learn more, go to the Palliative Care page.

    After Treatment

    When treatment ends, a person moves into a new phase of their cancer experience. For many patients, a lot of the after-treatment care will be given by healthcare providers in the community, like a family doctor or nurse practitioner.

    Follow-up Care

    Follow-up care is the care given after active treatment for colorectal cancer is over. It focuses on:

    • helping the person recover from the cancer and treatments
    • finding cancer early if it comes back

    To learn more about follow-up care, visit the Canadian Cancer Society.

    Managing Ongoing Symptoms

    A person may have symptoms from cancer for months or years after treatment has ended. These are called long-term effects or late effects.

    If you have ongoing symptoms after being treated for cancer, you can find information on how to manage them in our Symptom and Side Effect Management guides.

    End-of-Life Care

    Each person has a different experience during their final months and days of life. Their symptoms may change as their illness continues, and their needs for information and support will be unique. Family members will also have questions, concerns and needs of their own.

    If you are helping a family member through their final months of life, talk to your healthcare team about your questions and concerns as they come up. They can give you information and resources to support you and your family, and help you make decisions and plan for end-of-life care.

    For more information, go to the Palliative Care page.


    • Colorectal cancer is the second most commonly diagnosed cancer. Colorectal cancer is also the second most common cause of cancer death in Ontario.
    • An estimated 9,245 people in Ontario will be diagnosed with colorectal cancer and about 3,194 people will die from the disease in 2020.
    • One in 15 Ontarians is expected to be diagnosed with colorectal cancer in their lifetime, and 1 in 34 is expected to die from it.
    • Survival for colorectal cancer is average when compared with other cancers. People who are diagnosed with colorectal cancer have about a 67% chance of surviving 5 years after diagnosis compared with similar people in the general population.