Colorectal Cancer

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Overview

Colorectal cancer, also known as bowel cancer, colon cancer, or rectal cancer, is any cancer that affects the colon and the rectum. The colon and rectum make up the large intestine, which is part of the digestive system.

Most colorectal cancers start as a growth on the inner lining of the colon or rectum.

Our care

Learn more about the specialized care provided at Mount Sinai Hospital for colorectal and other gastrointestinal cancers.

This content is intended for informational purposes only and is not intended to be used or relied upon for any diagnostic or treatment purposes. It does not replace the need for consultation with a health-care professional. Please speak with your health-care professional for questions about your health.

Types

Types of colorectal cancer

Adenocarcinomas

Adenocarcinomas are cancer that start in the glands that line your organs. They can show up in different parts of your body. In colorectal cancer, adenocarcinomas start in the cells that make the mucus that lubricates the inside of the colon and rectum.

Adenocarcinomas are the most common type of colorectal cancer, making up about 95 per cent of cases. When physicians talk about colorectal cancer, they are almost always talking about this type.

Carcinoid tumours

Carcinoid tumours affect cells that make hormones and can occur in different parts of your body, although they often start in the gastrointestinal system. Most carcinoid tumours grow very slowly.

Gastrointestinal stromal tumours (GISTs)

Gastrointestinal stromal tumours (GISTs) start from special nerve cells in the wall of the colon and other digestive organs. These cells send signals to your muscles to help move food through the digestive system. When these cells grow and divide too much they can form a tumour.

Not all GISTs are cancerous. These tumours can be found anywhere in the digestive tract, but are not common in the colon.

Lymphomas

Lymphomas are a type of cancer that starts in the lymphatic system. Because there is lymphoid tissue throughout the body, lymphoma can start in many different body parts. Lymphomas that start in the colon are very rare.

Sarcomas

Sarcoma is a type of cancer that starts in blood vessels, muscle layers, or other connective tissues. Although sarcomas of the colon or rectum are rare, they can occur.

Colorectal cancer screening

Many people with colorectal cancer do not have any symptoms until their cancer is more advanced and more difficult to treat. Regular screening, even if you do not have any symptoms, can help detect colorectal cancer earlier, when it is much more likely to be cured.

Diagnosis

There are several tests used to diagnose colorectal cancer and more than one test is often needed to make an accurate diagnosis.

Learn about Mount Sinai’s Colorectal Diagnostic Assessment Program (DAP).

Fecal immunochemical test (FIT)

A fecal immunochemical test (FIT) is a special test of a small sample of your stool to see if there is blood in it. This test can detect blood that may not be visible.

A FIT is usually one of the first tests that is used to determine if a patient might have colorectal cancer.

Flexible sigmoidoscopy

Flexible sigmoidoscopy allows a physician to see the patient's rectum and sigmoid, which is the last part of the colon before the rectum.

During the test, a flexible, slender tube with a light and camera on it is inserted through the anus. The test takes a few minutes and is not painful, but it might be uncomfortable.

If the physician detects polyps (clumps of cells that can become cancerous over time) or colon cancer, we may recommend a colonoscopy to examine the entire colon and take out any polyps that are present so they can be examined.

Barium enema X-ray

A barium enema X-ray is a type of X-ray that helps the physician look at your lower intestine. Before the X-ray, the technician injects a liquid through the rectum (an enema) that contains a substance called barium sulfate, which makes the image clearer. In a double contrast barium enema, the technician adds air through the rectum as well.

If anything abnormal shows up on your barium enema X-ray the physician may recommend a colonoscopy.

Colonoscopy

A colonoscopy is a procedure that allows physicians to examine the large intestine (colon and rectum). During a colonoscopy, a long, flexible, slender tube, which is attached to a video camera and monitor, is inserted through the anus. The physician can see the entire colon and rectum on the monitor.

During this exam we remove any polyps (clumps of cells that can become cancerous over time) we find, as well as take tissue samples (biopsies) when needed.

Diagnostic imaging

Imaging, like computed tomography (CT) scans or magnetic resonance imaging (MRI) tests, helps physicians clearly see your colon and rectum. If something is detected, you may need further testing.

Cancer staging

If cancer is found, the next step is determining the stage of cancer. Knowing the stage of your cancer helps your care team develop your treatment plan. Physician determine the stage of your cancer based on the size and location of the tumour, whether cancer cells are in the lymph nodes and whether there are cancer cells in other parts of the body.

Treatment

If you have been diagnosed with colorectal cancer, your Cancer care team will discuss your treatment options and help you weigh the benefits of each treatment option against the possible risks and side effects.

Surgery is the most common treatment for colorectal cancer. During this surgery your surgeon removes the tumour, as well as part of the healthy colon and lymph nodes near the tumour.

In some cases you may need a combination of chemotherapy, radiation and surgery to treat colorectal cancer.

Clinical trials

You may be able to participate in a research study that helps physicians and researchers find ways to improve treatments and quality of life for patients living with colorectal cancer.