Colorectal Cancer

In Canada, roughly one in 14 people will develop colon cancer during their lifetime, and almost 95% of these cases appear after the age of 50.

Colon cancer, or colorectal cancer, originates in the cells of the colon or rectum. It usually develops in polyps, small wart-like masses of flesh that appear on the inner walls of the large intestine, also known as the colon.

Colorectal cancer can be detected by performing an iFOBT (immunochemical fecal occult blood test), followed by a colonoscopy if the test result is positive. Please note that the iFOBT alone is not enough to establish a diagnosis.

Colon cancer can be easily treated when diagnosed in its early stages. For this reason, it is preferable to screen for blood in the stool at the recommended interval, i.e. every two years for people aged 50 to 74.

The majority of people diagnosed with colon cancer are over the age of 50, and the risk increases with age. Over the course of their lifetime, one in 16 men is at risk of developing this type of cancer, while the rate for women is one in 18.

Sometimes, a person who has colon cancer shows no signs or symptoms in the early stages of the disease. Indeed, symptoms usually appear as the tumour develops.

Here are some signs and symptoms that may indicate colorectal cancer:

• Worsening constipation
• Sensation that the rectum is not completely empty after a bowel movement
• Red or very dark blood in the stool
• Prolonged diarrhea
• Pain or discomfort in the rectum

The first step is to perform an iFOBT (faecal occult blood test). This test detects the presence of tiny amounts of blood in the stool, not visible to the naked eye. In the event of a positive result, the physician will prescribe an additional examination, a colonoscopy, to confirm the potential presence of cancer or polyps.

Screening is aimed at preventing colon cancer by detecting, as the case may be: • Pre-cancerous polyps, which can be removed before they develop into cancer • Early-stage cancer, before symptoms appear, thereby increasing the chances of a full recovery

Colon cancer screening is recommended every two years for people between the ages of 50 and 74 who are at average risk (with no symptoms or other risk factors).

For people who have a family history, screening may start earlier on the advice of a physician.

The iFOBT is the best way to prevent colon cancer, as it can detect precancerous lesions, which can then be removed by colonoscopy before they develop into cancer.

The iFOBT is a quick, painless and non-invasive screening test that you can do at home.

When colon cancer is detected and treated at an early stage (stage 1 or 2), the likelihood of a successful treatment increases considerably, as the progression of the cancer is interrupted. However, as this type of cancer has few or no symptoms in its early stages, it can progress silently. As a result, almost half of all colorectal cancers are diagnosed at stage 3 or 4, when the cancer has spread elsewhere in the body (metastasized), thereby reducing survival rates.

The best way to prevent colon cancer is to do iFOBT screening at the recommended frequency.

Since the iFOBT cannot confirm the presence of cancer, a colonoscopy is required in order to make a diagnosis. Indeed, out of 36 people who receive a positive iFOBT result:

• Four have colorectal cancer.
• 17 have one or more polyps removed during the colonoscopy.
• 15 have neither cancer nor polyps.

Colonoscopy enables the physician to observe the inner lining of the colon and rectum. It is an invasive, in-clinic examination that can cause discomfort and requires intestinal preparation.

Among other things, this examination makes it possible to:

• Understand the causes of blood in the stool or abdominal pain.
• Detect the presence of colorectal cancer or polyps (polyps are removed during the examination, if present)
• Perform a biopsy (remove tissue for analysis).
• Check for inflammation in certain areas of the colon.
• Follow up on abnormal results with other tests, such as stool analysis.
• Follow up after colon cancer surgery.

In the event of an abnormal colonoscopy result, a healthcare professional will recommend additional tests, follow-up or further treatment, depending on the case.

Despite its inconveniences, colonoscopy is the diagnostic method of choice for colorectal cancer. During a colonoscopy, the healthcare professional may perform a biopsy, if necessary, or remove polyps (precancerous or not), if present.

Yes, other options may be available, depending on your situation. For example, in the event that an optical colonoscopy cannot be done, it is possible to perform a virtual colonoscopy, which involves observing the colon using medical imaging (X-rays). However, this type of colonoscopy does not allow for biopsy or removal of polyps. It is advisable to discuss this with your gastroenterologist to determine a treatment protocol adapted to your situation.

When colorectal cancer is diagnosed, the patient meets with the care team to discuss the treatment. This may involve surgery, chemotherapy or a combination of both, depending on the location of the tumour, where the cancer has reappeared (in the event of recurrence), the stage of the cancer, as well as the patient’s overall health condition and choice.

Are you concerned about colorectal cancer? Please fill out our brief questionnaire to confirm your eligibility for the screening program and order your kit.