Colorectal Cancer:
Diagnosis And Staging

This page covers tests that are often used to help diagnose and stage colorectal cancer.
Depending on the symptoms you have, you may also be asked to undergo other tests and investigations.

“You never know how strong you are until being strong is the only
choice you have.”

Cayla Mills

Diagnostic Tests to Determine Cancer Type

Once the doctor is sure of an abnormality, the following tests are done to determine further details about the type of cancer present.

These tests are used to supplement blood tests such as the complete blood count (CBC) and certain tumour marker tests.

Biopsy

What to expect

Biopsy involves the removal of a sample of cells or tissues for laboratory testing and is the only definitive method to diagnose colorectal cancer. It is a way to evaluate a suspicious area in your colon to determine whether it is cancerous.

Typically, the biopsy will be done along with the colonoscopy (Link to Screening – Colorectal Cancer – Colonoscopy). It is important that you choose a doctor and clinical team that you are comfortable with to perform your procedure.

The fine-needle aspiration (FNA) biopsy is generally used for colorectal cancer. This is a quick, simple test in which a thin needle is used to remove tissue or fluid for examination under a microscope.

For a few days after the biopsy, your abdominal area may feel sore and bruised. Don’t hesitate to talk to your clinical team about pain medication if you feel you might need it. The pain and bruising will generally subside in a couple of weeks. If it persists, please contact your doctor immediately.

Diagnostic Tests to Determine Stage and
Spread of Cancer

Chest X-Ray

What to expect

A chest X-ray is a type of imaging study and is generally painless. An image of the organs and bones is taken by projecting an energy beam through the body onto film. It is important that you choose a doctor and clinical team that you are comfortable with to perform your X-ray.

If you are pregnant or breastfeeding, be sure to inform your doctor before the X-ray.

During a chest X-ray:

You may be asked to change into a hospital gown and remove your jewellery, watch, body piercings or any other accessory that contains metal.

The X-ray technician will direct you to stand next to a “plate”, which may contain X-ray film or special sensors to record the images.

Next, the technician will tell you how to stand and instruct you to hold your breath while the images are taken. This ensures that the chest is completely still so the images are clear.

Images will be taken of both the front and side views of your chest.

After the images have been captured, you can change and put on your jewellery and any other accessories you may have removed.

The X-ray should take about 10-15 minutes.

Barium Enema

What to expect

A barium enema (also called a lower GI series) is a type of imaging study and is generally painless. In this study, a series of X-rays or the colon and gastrointestinal tract is taken by projecting an energy beam through the body onto film. The study involves the injection of a liquid containing barium (a metallic substance) into your rectum through a small tube. It is important that you choose a doctor and clinical team that you are comfortable with to perform your study.

Prior to the procedure, you will need to ensure that your colon is empty. Any residue may obscure the view of the internal organs during the exam. In order to ensure that the colon is empty, your doctor may ask you to:

Refrain from taking solid foods the day before the procedure

Have clear liquids (such as plain water, black tea or black coffee or juices)

Have clear liquids (such as plain water, black tea or black coffee or juices)

Take a laxative

Have an enema

It is important that you follow the instructions given by your doctor in order to ensure a successful procedure. Be sure to inform your doctor prior to the procedure if:

You are pregnant or breastfeeding

You have previously had an allergic reaction to sedatives

You are taking any vitamins, supplements, ayurvedic medicines or homeopathic medicines

During a barium enema:

You may be asked to change into a hospital gown and remove your jewellery, watch, body piercings or any other accessory that contains metal. You may also be asked to empty your bladder.

You may be given a mild sedative or pain medication, either in a pill form or through an IV, to minimize discomfort during the procedure.

You will then be instructed to lie on your side on a specially-designed examination table, usually with your knees drawn towards your chest.

Try to relax, as this will make the procedure more comfortable for you.

First, an X-ray will be taken to make sure that the colon is clean.

Next, a lubricated enema tube will be inserted into your rectum. A barium bag will then be connected to the tube to deliver the barium solution into the colon.

As your colon fills with the barium liquid, you may have the urge to pass gas or have a bowel movement. You may also experience mild abdominal cramping.

Next, the specialist will tell you how to position your body and instruct you to hold your breath while the images are taken. This ensures that the body is completely still so the images are clear.

The specialist may also press firmly on your abdomen and pelvic area, manipulating your colon for better viewing.

A number of images will be taken of the colon, from multiple angles.

After the images have been captured, the enema tube will be removed. You can then ask to use the restroom to expel any additional liquid or air.

You can then change and put on your jewellery and any other accessories you may have removed.

The study should take about 30 minutes to an hour.

After the study, you may receive special instructions regarding the barium liquid in your system. For example, your technician or doctor may ask you to wait for a few minutes to ensure that you do not have an allergic reaction. You may also be told to drink plenty of fluids to help your body to flush out the liquid.

CT Scan

What to expect

A CT (computerized tomography) scan is an imaging study and is generally painless. It uses X-rays to take multiple images of the body from different angles to recreate three-dimensional pictures of your internal organs on a computer. It is important that you choose a doctor and clinical team that you are comfortable with to perform your CT scan.

You may be asked to refrain from eating or drinking for a few hours before your scan. Be sure to inform your doctor prior to your scan if

You are pregnant or breastfeeding

You have any metal or electronic
devices implanted in your body (such
as a pacemaker or metal pins)

You are afraid of enclosed spaces
(claustrophobic)

You have previously had an allergic
reaction to contrast material

You are taking any vitamins, ayurvedic
medicines or homeopathic medicines

During a CT scan

You may be asked to change into a hospital gown and remove your jewellery, watch, body piercings or any other accessory that contains metal. You may also be asked to empty your bladder.

You may be given a special dye (called contrast material) which can help highlight the areas of your body that are being examined. The dye can be given to you by mouth (in a drink), by injection through a vein in your arm or by an enema in your rectum. You may need to wait for 30 minutes to an hour for your body to absorb the dye.

Next, a nurse or technician will take you to the room which contains the CT scanner. You will be asked to lie on a narrow, motorized table that will slide you into the machine. The nursing staff may use straps to keep you in position. You can ask for a pillow if you are feeling uncomfortable. You will be asked to remain still for the duration of the scan.

As the table moves you into the CT scanner, various detectors and X-ray tubes will rotate around you. Each rotation will produce several cross-section images of your body. You may hear some buzzing or whirring noises – try not to be alarmed and remember to stay still.

The technicians will be seated in a separate room, but they will be able to see and hear you. You may be asked to communicate with them via intercom. They may ask you to hold your breath at certain times to improve image quality.

The scan will usually take 20-30 minutes to complete.

After the scan, you may receive special instructions regarding the contrast material. For example, your technician or doctor may ask you to wait for a few minutes to ensure that you do not have an allergic reaction. You may also be told to drink plenty of fluids to help your kidneys to flush out the contrast material through your urine.

PET Scan

What to expect

PET (Positron emission tomography) scan is a process that uses radioactive glucose to detect malignant tumour cells in the body. Malignant tumour cells show up brighter in the picture because they are more active and take up more glucose than normal cells do. The scan is generally painless. It is important that you choose a doctor and clinical team that you are comfortable with to perform your PET scan. Some hospitals have a combined PET/CT scanner.

You may be asked to refrain from eating or drinking for a few hours before your scan. Be sure to inform your doctor prior to your scan if:

You are pregnant or breastfeeding

You have any metal or electronic
devices implanted in your body (such
as a pacemaker or metal pins)

You are afraid of enclosed spaces
(claustrophobic)

You have previously had an allergic
reaction to contrast material

You are taking any vitamins, ayurvedic
medicines or homeopathic medicines

During a PET scan:

You may be asked to change into a hospital gown and remove your jewellery, watch, body piercings or any other accessory that contains metal. You may also be asked to empty your bladder.

You may be given a special dye (called contrast material) which can help highlight the areas of your body that are being examined. The dye can be given to you by mouth (in a drink), by injection through a vein in your arm or by an enema in your rectum. You may need to wait for 30 minutes to an hour for your body to absorb the dye.

Next, a nurse or technician will take you to the room which contains the PET scanner. You will be asked to lie on a narrow, motorized table that will slide you into the scanner. The nursing staff may use straps to keep you in position. You can ask for a pillow if you are feeling uncomfortable. You will be asked to remain still for the duration of the scan.

As the table moves you into the PET scanner, the machine will begin to rotate around you. Each rotation will produce several cross-section images of your body. You may hear some buzzing or whirring noises – try not to be alarmed and remember to stay still.

The technicians will be seated in a separate room, but they will be able to see and hear you. You may be asked to communicate with them via intercom.

The scan will usually take about 30 minutes to an hour to complete.

After the scan, you may receive special instructions regarding the contrast material. For example, your technician or doctor may ask you to wait for a few minutes to ensure that you do not have an allergic reaction. You may also be told to drink plenty of fluids to help your kidneys to flush out the contrast material through your urine.

MRI Scan

What to expect

Magnetic resonance imaging (MRI) scan is a procedure in which an MRI scanner uses a high-powered magnet and a computer for comprehensive images of the internal organs and surrounding structures. MRI scans normally add supplementary information about anomalies in the colon and may be recommended only in select cases. The scan is generally painless. It is important that you choose a doctor and clinical team that you are comfortable with to perform your MRI scan.

You may be asked to refrain from eating or drinking for a few hours before your scan. Be sure to inform your doctor prior to your scan if:

You are pregnant or breastfeeding

You have any metal or electronic
devices implanted in your body (such
as a pacemaker or metal pins)

You are afraid of enclosed spaces
(claustrophobic)

You have previously had an allergic
reaction to contrast material

You are taking any vitamins, ayurvedic
medicines or homeopathic medicines

During a MRI scan:

You may be asked to change into a hospital gown and remove your jewellery, watch, body piercings or any other accessory that contains metal. You may also be asked to empty your bladder.

You may be given a special dye (called contrast material) which can help highlight the areas of your body that are being examined. The dye is typically administered by injection through a vein in your arm. You may need to wait for 30 minutes to an hour for your body to absorb the dye.
Next, a nurse or technician will take you to the room which contains the MRI machine. You will be asked to lie on a narrow, motorized table that will slide you into the machine. The nursing staff may use straps to keep you in position. You can ask for a pillow if you are feeling uncomfortable. You will be asked to remain still for the duration of the scan.
As the table moves you into the MRI machine, the machine creates a strong magnetic field around you and radio waves are directed at your body. You may hear repetitive noises such as thumping or tapping – try not to be alarmed and remember to stay still. You can request earplugs or have music playing to help you block out the noise.

The technicians will be seated in a separate room, but they will be able to see and hear you. You may be asked to communicate with them via intercom.

The scan will usually take about 30 minutes to an hour to complete.

After the scan, you may receive special instructions regarding the contrast material. For example, your technician or doctor may ask you to wait for a few minutes to ensure that you do not have an allergic reaction. You may also be told to drink plenty of fluids to help your kidneys to flush out the contrast material through your urine.
How Colorectal cancer is staged

The results of your diagnostic tests will help your doctor determine the size and position of the cancer, and whether it has spread. This is called staging. Knowing the stage and grade of your cancer will help your doctor plan the best course of treatment for you.

There are different systems for describing the stage of stomach cancer.

THE TNM STAGING SYSTEM

The TNM staging system gives the complete stage of the cancer

T describes how far the tumour has grown into the stomach wall.

N describes whether the cancer has spread to the lymph nodes and which nodes are involved. For example, N0 means no lymph nodes are affected. N1 means there are cancer cells in 1 to 3 of the lymph nodes.

M describes whether the cancer has spread to another part of the body. For example, M0 means the cancer has not spread (metastasised) to other parts of the body.

Sometimes the final TNM staging may not be certain until surgery is completed, since the tissue samples removed during the procedure will need to be analysed further.

THE NUMBER STAGING SYSTEM

Colorectal cancer can also be divided into five number stages.

Stage 0 is when abnormal cells have formed in the innermost lining of the colon wall. These abnormal cells may become cancerous and spread to the nearby tissues. Stage 0 is also called carcinoma in situ.

Stage I is when cancerous cells have formed in the innermost lining of the colon wall, and may have spread into the next layer (submucosa) or the thick muscle layer of the colon wall.

Stage II colorectal cancer is further divided into stages IIA, IIB and IIC, depending on where the cancer has spread.In stage IIA, cancerous cells have spread into the submucosa layer, the thick muscle layer and the outermost layer (serosa) of the colon wall.In stage IIB, the cancer has typically spread through the serosa into the tissue that lines the abdominal organs (the visceral peritoneum).In stage IIC, the cancer has spread through the serosa into nearby organs.

Stage III colorectal cancer is sometimes called locally advanced colorectal cancer. It is further divided into stages IIIA, IIIB or IIIC, depending on where the cancer has spread.In stage IIIA, the cancerous cells have typically spread into the muscle layer, serosa and 1-3 nearby lymph nodes.In stage IIIB, the cancerous cells have typically spread into the muscle layer, serosa and 4-6 nearby lymph nodes.In stage IIIC, the cancer has spread into the muscle layer, the tissue that lines the abdominal organs (the visceral peritoneum), 7 or more nearby lymph nodes or a nearby organ.

Stage IV colorectal cancer is also called secondary or metastatic colorectal cancer. It is further divided into stages IVA, IVB or IVC, depending on where the cancer has spread. In stage IVA, the cancerous cells have typically spread into one area or organ that is not near the colon, such as the liver or lungs. In stage IVB, the cancerous cells have typically spread into more than one area or organ that is not near the colon, such as the liver, lungs or distant lymph nodes.In stage IVC, the cancer has spread into the tissue that lines the abdominal organs (the visceral peritoneum) and may have spread into other areas or organs.

GRADING

The grade of a cancer gives an idea of how slowly or quickly it might grow. The grade is based on how the cancer cells look under a microscope when they are compared with normal cells.

Grade 1 (low grade cancer): The cancer cells look similar to normal cells (they are well differentiated). They usually grow slowly. These cancer cells are less likely to spread.

Grade 2 (moderate or intermediate-grade cancer): The cancer cells look more abnormal and grow slightly faster than grade 1 cells.

Grade 3 (high-grade cancer): The cancer cells look very different from normal cells (they are poorly differentiated). They may grow more quickly than grade 1 or 2 cells.

Treatment options for colorectal cancer

The decision about the best course of treatment is based on these test results and the type, stage, grade and size of your tumour. Treatments like surgery, chemotherapy and radiation therapy are some of the options used for colorectal cancer. Refer to this section to understand the types of cancer treatments for colorectal cancer and possible side effects. Read more

Your cancer journey

Everyone deals with a cancer diagnosis and treatment in a different way. Refer to this section to understand
various aspects of your cancer journey and the road to recovery. Read more

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