About Colorectal Cancer
img arrowhead white righticon expand arrow
ccran about

What is colorectal cancer?

Colorectal cancer is a cancer that starts in the cells that line either the colon or the rectum. These cancers can also be named colon cancer or rectal cancer respectively, depending on where they start. Colon cancer and rectal cancer are often grouped together because they have many features in common.

Colorectal cancer usually starts from a polyp, a growth that originates from the lining of the colon or rectum. Polyps are benign entities and can take 3-5 years to develop and an additional 2-3 years to turn cancerous. Finding and removing polyps can prevent colorectal cancer.

Most colorectal cancers are adenocarcinomas, which are cancers that begin in cells that line the inner colon or rectum. Cancer starts when cells in the body begin to grow out of control. Cells in nearly any part of the body can become cancerous and can spread to other areas of the body.

ccran scan 4

How Cancer affects the Colorectum

The colon is a 6-foot long muscular tube connecting the small intestine to the rectum. The colon–which along with the rectum is also known as the large intestine–is a highly specialized organ that is responsible for processing digestive waste so emptying the bowels is easy and convenient. The colon removes water from the stool (digestive waste matter) and stores the solid stool. Once or twice a day, it empties its contents into the rectum to begin the process of elimination.

The rectum is a 6-8-inch storage chamber that connects the colon to the anus. It is the rectum’s job to receive stool from the colon, to let you know there is stool to be evacuated, and to hold the stool until you are ready to evacuate that stool.

During digestion, food moves through the stomach and small intestine into the colon. The colon absorbs water and nutrients from the food and stores stool. Stool moves from the colon into the rectum before it leaves the body.

Cancer begins when normal cells begin to change and grow uncontrollably, forming a mass called a tumor. A tumor can be benign (noncancerous) or malignant (cancerous, meaning it can spread to other parts of the body).

Depending upon the size, location and spread of the cancer, different modalities of therapy may be employed to treat the disease. It is important to fully understand the various treatment options available when managing the disease, whether the objective involves curative intent or promoting longevity and a good quality of life. The colon and rectum are made up of different layers of tissues. A polyp will start in the innermost layer (mucosa) of the colorectum and then grow toward the outer layers (one layer at a time).

If a tumour has grown through all layers of the colon or rectum, it may then spread to the nearby lymph nodes or tissue.

ccran scan 3

Basic Anatomy of the Gastrointestinal (GI) System

The large intestine is also known as the large bowel and commonly referred to as the colorectum or just the colon. The colon’s main function is to reabsorb large quantities of water and nutrients from undigested food products. If too much water is reabsorbed, constipation may result. Not absorbing enough water may result in diarrhea.

The rectum’s main function is to store feces, or waste material, before being expelled from the body. The colon itself is divided into different parts. It extends from the cecum to the anus and includes the following five component parts:

corol cancer en

Each part of the colorectum serves a specific function in the elimination of waste. In the digestive process, the colon’s main functions are to:compact the chyme (liquefied food)absorb excess water from the chymereceive the B-vitamins that are produced by healthy intestinal bacteriamove compacted chyme and dead bacteria into the rectum and out of the body.


Colorectal Cancer and Genetics

Not all colorectal cancers are hereditary, but all colorectal cancers are caused by genetic mutations.

Approximately 70-75% of colorectal cancers are sporadic: these are cancers that occur in people who do not have a family history of that cancer or an inherited change in their genetic material (DNA) that would increase their risk for that cancer.

All cancers are the result of gene mutations. The vast majority are sporadic occurrences with only some caused by hereditary genetic syndromes. Genetic conditions involve a largely unpredictable interplay of many factors and processes. Just because you hold a genetic mutation for something does not necessarily mean it will be expressed in your lifetime, but knowing your risk can save your life. Please read on to learn more about the genetics behind colorectal cancer.

To learn more about the role of genetics in colorectal cancer, check out our information booklet.

ccran staging

Colorectal Cancer Staging

If a person has been diagnosed with colorectal cancer, one of the first things they will want to know is the stage of their cancer. The stage refers to the extent of the cancer or how far it has spread. The stage of colon or rectal cancer is important because it will determine the best therapeutic approach in the management of the disease.

The tool used to describe the stage of a patient’s disease is the TNM Staging System. Doctors use the results from diagnostic tests and scans to answer these questions:

Tumor (T): Has the tumor grown into the wall of the colon or rectum? If so, how many layers of the colorectal wall are affected?
Node (N): Has the tumour spread to the lymph nodes? If so, where and how many lymph nodes are involved?
Metastasis (M): Has the cancer spread to distant organs of the body? If so, where and how many organs are involved?

The results are combined to determine the stage of cancer for each person.

For colorectal cancer, staging often can’t be completed until after surgical resection of the primary tumour has taken place to remove the primary tumour along with surrounding tissue containing lymph nodes, and possibly lesions found on other organs.

There are five stages (Stage 0 through IV) to colorectal cancer. After each element has been determined, they are combined to form an overall stage of the cancer in roman numerals. The higher the roman numeral, the more advanced the cancer. This is generally how the cancer is referred to between doctor and patient:

  • Stage 0: The cancer is confined to the innermost layer of the colon or rectum. It has not yet invaded the colorectal wall. It is also referred to as high grade dysplasia or an in-situ cancer.
  • Stage I: The cancer has penetrated some or several layers of the colon or rectum wall.
  • Stage II: The cancer has penetrated the entire wall of the colon or rectum and may extend into nearby tissue(s).
  • Stage III: The cancer has penetrated the entire wall of the colon or rectum and has spread to the regional lymph nodes.
  • Stage IV: The cancer has penetrated the entire wall of the colon or rectum, has spread to the regional lymph nodes, and has further spread to distant organs, usually the liver or lungs.

As colorectal cancer progresses from Stage 0 to Stage IV, the cancer cells grow through the layers of the rectum wall and spread to lymph nodes and then to distant organs. The liver and lungs are the most common sites of spread in patients with colorectal cancer.

The size of the colorectal tumor does not appear to be important when it comes to outcomes. The aggressiveness of colorectal cancer is based entirely upon its ability to grow and invade the colorectal wall, lymphatic system, and blood vessels.

ccran diagnosis

Diagnosing Colorectal Cancer

While some people start the journey due to routine recommended checkups (screening), others do so because of troubling symptoms, or an abnormal physical exam, or a new finding on a lab test such as iron deficiency anemia. Screening, such as FOBT and FIT, is intended for the “average risk Canadian” – a person who does not have symptoms from colorectal cancer and does not have a first degree relative who was diagnosed with colorectal cancer. It typically is recommended for people aged 50 and older, but the test cannot officially diagnose colorectal cancer. Instead, a diagnostic (rather than a screening) test is required such as a colonoscopy, biopsy, or imaging tests to confirm the diagnosis of colorectal cancer, as well as to define the extent of the disease.If a screening test such as FOBT or FIT has come back positive, your doctor will recommend that you undergo a diagnostic colonoscopy. Your doctor may also recommend such a test if symptoms or the results of a physical exam or blood tests suggest that colorectal cancer might be present.

Statistics & Risk Factors
icon expand arrow
ccran stats

Colorectal Cancer Statistics

Colorectal Cancer Resource & Action Network (CCRAN) has issued the following summary based on the latest Canadian Cancer Statistics issued by the Canadian Cancer Society, Statistics Canada, the Public Health Agency of Canada and the Provincial/Territorial Cancer Registries. We have presented colorectal cancer-relevant information but should you wish to view the publication concerning all statistics, it can be found here.

Colorectal Cancer Risk Factors

We don’t really know why colorectal cancer develops in some people and not in others. However, the same risk factors have been identified over the years which increase a person’s risk of developing colorectal cancer.

A risk factor is something that may increase a person’s chances of developing a disease or condition. Risk factors for colorectal cancer can be divided into two main groups: those that you cannot change and those that are lifestyle-related and, therefore, can be changed by you.

Symptoms & Prevention
icon expand arrow
ccran symptom

Symptoms of Colorectal Cancer

In the early stages of colorectal cancer, many people often do not experience any symptoms. This is why the disease is often referred to as “silent”.

When symptoms do appear, they will likely vary, depending on the cancer’s size and location in the large intestine–also known as the colorectum–which is comprised of the colon and the rectum. Symptoms of colorectal cancer may include:

  • Bloody stools
  • Prolonged constipation/diarrhea
  • Narrow stools
  • Abdominal cramping
  • Unexplained weight loss/loss of appetite
  • Sense of fullness
  • Nausea and vomiting
  • Gas and bloating
  • Fatigue/lethargy

Recent studies indicate that, on average, patients will typically be diagnosed approximately 14 weeks after the onset of their symptoms. There is no association between overall duration of symptoms and the stage of the tumor. Therefore, it is best to get regular screenings rather than rely on colorectal cancer symptoms to alert one to the presence of a tumor, as colorectal cancer can grow for years before causing any symptoms.

ccran prevention

Prevention of Colorectal Cancer

Colorectal cancer is the second leading cause of cancer death in Canada, but it is also a cancer that we may be able to prevent.

According to research, approximately 50% of cancer incidences are said to be preventable through the adoption of a healthy diet, physical activity, and weight management. Cancer prevention entails measures taken to lower the chance of getting cancer. To prevent new cancers from developing, scientists look at risk factors and protective factors.

Anything that increases your chance of developing cancer is called a cancer risk factor.

Conversely, anything that decreases your chance of developing cancer is called a cancer protective factor. Recommendations to help prevent colorectal cancer include:

  • Eating a diet rich in fruits, vegetables, whole grains, and beans
  • Maintaining a healthy weight
  • Being physically active
  • Meeting your nutritional needs through diet, not supplements
  • Limiting consumption of red and processed meat
  • Limiting consumption of “fast foods” and other processed foods high in fat, starches, and sugar
  • Limiting consumption of sugar-sweetened drinks
  • Limiting alcohol consumption
  • Not smoking
ccran screening

colorectal cancer screening

Colorectal cancer is the third most diagnosed cancer in Canada. It is the second leading cause of death from cancer in Canadian men and the third leading cause of death from cancer in Canadian women. It is, however, the most preventable cancer through screening!

Screening means checking for a disease in a group of people who do not show any symptoms of the disease. Cancer screening tests help find colorectal cancer before any symptoms develop and signs of colorectal cancer are discovered by your doctor. When colorectal cancer is found and treated early, the chances of successful treatment are far better.

Colorectal cancer typically starts as a polyp – a benign growth in the lining of the colon or rectum. If left unremoved, these polyps grow in size and can also grow in number in the colon or rectum. In time (5-10 years), these polyps may become malignant (cancerous), capable of invading nearby tissue and distant organs, such as the liver or lungs. Screening for polyps or early-stage tumours will help ensure treatment is most effective before the disease spreads outside the colon or rectum and signs of colorectal cancer manifest.

Speak to your doctor to discuss your risk and determine the most appropriate screening plan for you. It could save your life.

My Colorectal Cancer Consultant
icon expand arrow
ccran coach

My Colorectal Cancer Consultant

My Colorectal Cancer Consultant is an online tool designed by CCRAN to provide colorectal cancer patients in advanced stages with information about potential treatment options that they can discuss with their treating colorectal oncologist. Patients will be guided through a series of questions requiring their pathology report. At the end, they will receive a personalized report that outlines the potential treatment options that may be appropriate for them based on their individual diagnosis.

The goal is to help patients have a thoughtful discussion with their treating oncologist by providing them with more evidence-based information on the potential colorectal treatment options available. My Colorectal Cancer Consultant was designed  to encourage informed and joint decision-making between the patient and their treating oncologist. Complete the questionnaire today and learn more about your potential treatment options!

icon expand arrow
ccran treatment

Colorectal Cancer Treatment

A diagnosis of colorectal cancer can be overwhelming. This colorectal cancer treatment guide was developed to help you throughout your cancer journey. Each person is different, and a personalized approach to colorectal cancer treatment takes into account factors related to your tumour, your body, and your preferences. Advances in research over recent years have meant that more treatment options than ever are available to meet the needs of individual patients.

CCRAN has prepared descriptions of treatments according to each stage of the disease: surgery, radiation therapy, chemotherapy, and targeted anti-cancer drugs.

ccran testing

What Are Biomarkers?

An exciting scientific development in recent years has been the identification of biomarkers ─ molecules found in your tumour or other tissues that can reveal whether a process in your body is normal or pathogenic (causing disease).

Biomarkers, short for biological markers or molecular markers, include DNA, proteins, and genetic mutations found in blood, tissue, or other body fluids. Biomarker testing is sometimes called tumour testing, molecular testing, and genomic testing.

If you have been diagnosed with stage IV colorectal cancer, it is crucial to know your tumour’s biomarker profile so that your care team can develop a personalized colorectal cancer treatment plan for you. Knowing your biomarker profile can help you and your care team better understand the characteristics of your tumour and to personalize your treatment plan.

ccran sideeffects

Treatment-Induced Side Effects

Treatment of your colorectal cancer – whether by surgery, radiation, chemotherapy or targeted medications (or a combination of these) – may result in side effects.

While some side effects are unpleasant, it is often because the treatment is working to destroy colorectal cancer cells and, in the process, some healthy tissues are also affected. Side effects can be seen as a sign that the therapy is working ─ it’s doing its job of destroying colorectal cancer cells!

Many side effects are expected, manageable, and pose no danger to you. Remedies are available for many of these treatment-induced side effects. Most side effects are temporary, and once treatment is completed, they will disappear over time as your body heals from the anti-cancer treatment and healthy cells start to regrow.

CCRAN has developed an online tool to help patients who are undergoing systemic therapy (chemotherapy, targeted therapy and immunotherapy). This tool will assist with treatment induced side effects by providing the user with a description, cause and remedy to the treatment induced side effect. Please visit "My Colorectal Cancer Treatment Side Effects" online tool

ccran trials

What Are Clinical Trials?

Clinical trials are studies that involve people and test many types of interventions including drugs, devices, genetic therapies, natural health products, psychotherapies, and lifestyle and preventative care interventions.

Treatment Clinical Trials

Conducting clinical trials for potential new treatments allow doctors and researchers to get a better understanding of how those treatments will perform on patients. By testing new treatments, doctors will be able to determine if the new treatment works better than the standard treatment.

Not all treatments have to be novel. The treatment can already be in use, but more evidence is required on how it works. Once treatments are approved and become one of the standard treatments, they can be tested on other types of cancers.

A regimen will be created to provide patients with the correct dosage to increase the effectiveness of the treatment. The treatment being studied has the potential to be lifesaving, life extending, and/or improve the quality of life. New treatments are monitored through clinical trials to ensure they are safe and effective.

Why are Clinical Trials Done?

Clinical trials are done for numerous reasons that benefit the patient as well as medical research.

  • Patients who take part in a clinical trial will have first access to a new treatment that is not yet available.
  • Clinical trials are the only reliable, acceptable, scientific method of potentially bringing new treatments to light.
  • Volunteering in a clinical trial can benefit the patient as well as move medical research forward.
  • The results from the clinical trials provide information that allows new treatments to replace the older treatments or add to the list of already existing treatments.
  • Clinical trials provide potential treatment to patients in various stages whether they are in the early or late stage.
  • As more adults participate in clinical trials, new treatments can be developed sooner.
ccran trial 2

Types of Clinical Trials

There are clinical trials used to screen, prevent, and treat a specific disease.

Screening Trials: Look for more effective screening techniques to detect cancer before symptoms become present.

Prevention Trials: Find new treatments that could help prevent cancer.

Treatment Trials: Performed in phases and compares two or more treatments to either the standard treatment or a placebo*. In clinical trials, the participants are assigned randomly to either the treatment group or the control group (standard treatment). Having the clinical trials blinded and randomized avoids bias–neither the patient nor the doctor knows which group a patient is assigned to. This avoids having an influence on the study results.

*Placebos contain no active medication and can be used instead of the standard treatment but are not typically used in cancer clinical trials due to ethical reasons.

Phases of Clinical Trials

Clinical trials are done in phases to monitor the safety and effectiveness of the treatment. Please download PDF to learn more about the phases of clinical trials.

Phase 1:
This phase can be referred to as “first in humans” since it is the first time the treatment is being tested on people. Testing is done on a small number of participants (100 or fewer). The goal of phase 1 is to determine the correct dosage, dosage schedule, how the treatment should be delivered, and potential side effects. The main purpose is to ensure no major safety issues are associated with the treatment. Many different tumor types can be included in phase 1 testing.

Phase 2: This phase includes a specific patient population for whom the treatment is targeting. Testing is done on a larger number of participants (approximately 100). The main purpose is to monitor side effects and the effectiveness of the treatment.

Phase 3: This phase includes randomized testing of the new treatment against the control group (people who do not receive the treatment). The results will be compared to the standard treatment. Testing is done on a greater number of participants (1000 or more).

Phase 4: This phase takes place once the treatment has received approval. Once on the market, the treatment continues to be monitored in this phase.

ccran safety

Patient Safety

Patient safety is key when performing clinical trials and must be enforced. When a patient finds a potential clinical trial to participate in, a series of data points about the patient are collected at the beginning, such as age, race, and gender.

Another set of requirements are needed based on the patient’s disease, medical history, and current health. These requirements are part of the inclusion criteria and exclusion criteria. Inclusion criteria ensure the participants in the study are medically similar.

Exclusion criteria ensure the participants are kept safe by excluding them from the study due to the treatment possibly having a negative impact on the patient’s health.

A protocol is written based on the inclusion and exclusion criteria, which also includes a written description of the trial and has a set of rules the patient must follow during the clinical trial. Protocols would be requested for approval by the Institutional Review Board (IRB) to ensure patient safety and patient rights. Once approved, the Data Safety Monitoring Board (DSMB) will monitor the study throughout the clinical trial.

ccran insurance

Health Insurance for Clinical Trials Outside of Canada

Looking for clinical trials outside of Canada is a great option, but it is important to double check your health insurance coverage to determine what extent the provider will cover.

There are many factors that are considered when finding the right clinical trial for you, such as: the type of disease, the length of the study, side effects and any out-of-pocket costs when out of the country.

Even though clinical trials are a great option, the cost and the health insurance coverage are factors that have adults second guessing out of country clinical trials. Some clinical trials can be covered by the sponsor of the study, which is usually an organization such as a pharmaceutical company. Your health insurance may cover an out of country clinical trial based on the extent of coverage you have. The sponsor provides financial support for the study, tests the treatments on the patients and oversees the study and data collected.

If a patient submitted a request to a health provider and was not approved for coverage, the patient can always appeal the decision. Compassionate use of a treatment being studied can be given to a patient if they are in a serious or life-threatening condition of a disease and have exhausted other options.

ccran find

Find a Clinical Trial in Canada

Speak to your doctor to learn more about clinical trials. Once you have a better understanding, you can now start looking for clinical trials near you.

There are a number of clinical trial finders that can be a useful tool when searching for clinical trials such as:

  • Clinical Trials Ontario (CTO)
  • Canadian Cancer Trials
  • Trialjectory
  • ClinicalTrials.gov

It is important to input the most accurate information about yourself to obtain the best results. How do I search for colorectal cancer clinical trials?

Step 1: Identify your disease/condition
Step 2: Enter your location (e.g., city, province, and/or postal code)
Step 3: Enter the distance/range you are willing to travel
Step 4: Choose what clinical trial phase you would like to view (phase l, phase ll, phase ll, or phase lV)
Step 5: Enter your demographics, such as age, gender and medical history
Step 6: Add keywords to make your search more specific (e.g., drug name, biomarker status*, NCT number**, recruitment status)

*Biomarkers are biological molecules produced by the tumor that provide information on which treatment option is best suited for you.

**NCT number (National Clinical Trial Number) is a number given to a registered clinical trial and used as an identification given by the NCI (National Cancer Institute)

ccran treatment updates

Treatment Updates

Each month, CCRAN provides patients and caregivers with evidence-based information on the disease.

We perform comprehensive and systematic reviews of the literature every month to publish updates on treatments and clinical research, covering topics such as:

  • Drugs/Systemic Therapies
  • Surgical Therapies
  • Radiation Therapies
  • Psychosocial Oncology
  • Screening
  • Other
  • Nutrition/Healthy Lifestyle
  • COVID-19 Updates

Check out our most recent treatment and clinical research updates!

ccran naturopath

Naturopathic Medicine

Naturopathic Medicine is unique in how it treats the “why” of the disease. The body is seen as an ecosystem made up of various organs that depend on each other for survival (much like animals and plants depend on each other in the environment). When there are imbalances in our internal environment, we begin to see disease. Restoring a healthy internal environment to maintain a state of health is the goal of the naturopathic doctor.

Naturopathic Doctors are regulated health professionals in British Columbia, Saskatchewan, Manitoba, Alberta, and Ontario with:

  • 3 years of premedical undergraduate educational requirements
  • 4 years of naturopathic medical college
  • International and local licensing examination requirements

Among the different tools to treat the “why” are:

  • Clinical nutrition
  • Botanical medicine
  • Chinese medicine and acupuncture
  • Naturopathic manipulation
  • Lifestyle counseling
  • Hydrotherapy
  • Infusion (intravenous) therapy

Naturopathic medicine is an important part of colorectal cancer care. Over the past two decades, research has shown how integrative therapies can improve cancer patient treatment outcomes.

Naturopathic medicine offers therapies that support the individual throughout their cancer journey. Some of the potential benefits include:

  • Reduction in the risk of initially developing colorectal cancer
  • Supporting tolerability and treatment response with patients undergoing conventional cancer treatment including chemotherapy, radiation and/or surgery
  • Promoting patient’s return to optimal health and prevention of recurrence once cancer has been successfully treated

Supportive naturopathic cancer care has undergone tremendous growth and evolution over the past two decades. Recently, Dr. Eric Marsden ND, was the lead author on a publication outlining the principles of care guidelines for naturopathic cancer care which was published in Current Oncology in February of 2019.

ccran ostomies


The Ostomy Canada Society is a non-profit volunteer organization in Canada dedicated to all people with an ostomy and their families, helping them live life to the fullest through support, education, collaboration, and advocacy.
The following content has been provided by the Ostomy Canada Society. Additional content may be accessed from their website on support and services.

Please click on the following link to visit a host of services on support and education throughout Canada: https://www.ostomycanada.ca/