March is Colorectal Cancer Awareness Month, which is a month set aside to educate, raise awareness, and educate the general public about this devastating disease. Estimates show that over 150,000 people will be diagnosed with colorectal cancer in 2021, making it the 3rd most common cancer diagnoses in men and women outside of some skin cancers. Unfortunately, estimates show that 50,000 people will lose their battle with colorectal cancer this year. This cancer is the 2nd leading cause of cancer related deaths when combining both men and women. As such, you can see how raising awareness and educating the public on both the disease and prevention methods is such an important task. So, what is colorectal cancer, and how is it diagnosed? 

What is Colorectal Cancer?

Colorectal cancer is a malignant tumor of the large intestine which may affect either the colon or rectum. The colon consists of the five or six feet of the upper part of the large intestine, and the rectum is about 6 inches in length and is the lower part of the large intestine located just above the anal canal. 

Colorectal cancer is usually a slow developing cancer that begins as a non-cancerous polyp, which is an abnormal growth of tissue lining the colon or rectum. Cancer begins when healthy cells begin to change and then grow out of control. Unfortunately, most people show no symptoms in the early stages of the disease, and thus have no idea that it has been growing inside of them for a while. Normally, symptoms begin showing in the 3rd stage of colorectal cancer as the disease is spreading past the colon and into lymph nodes around the colon. At this point, the cancer is advanced and needs to be treated immediately. In the 4th stage, the cancer has spread to other organs in the body, like the liver and lungs, and the likelihood of someone surviving 5 years after diagnosis decreases significantly. 

Who does this cancer impact? Well, this cancer does not discriminate by gender, as women have almost as high of a chance of developing the disease as men. However, this type of cancer does seem to be associated in many ways with age, as the statistics show that the chances of one developing it under the age of 45 is much lower than those over the age of 45. As such, it is recommended outside of special circumstances (example: family history with colorectal cancer, personal history, genetics, race, etc.) that screening for colorectal cancer begins at age 45

How is Colorectal Cancer Diagnosed?

There are many tests doctors can use to find and diagnose colorectal cancer. They can also conduct tests to see how contained the cancer is or if it has spread to another part of the body from where it started. Doctors may also do tests to learn which treatments could work best.


A colonoscopy is a procedure that lets the doctor look inside the entire rectum and colon by way of a colonoscope, which is a long slender tube with a camera and light at the tip. This procedure is virtually painless, as the patient is sedated and isn’t aware of what is going on. The patient may experience minor discomfort after the procedure, but this usually subsides in a short amount of time. The procedure is conducted by a colonoscopist who specializes in performing this test. If colorectal cancer is found, the patient will undergo a complete diagnosis with further testing.

Colonoscopies are an important screen to have conducted on a regular basis as directed by your doctor. They are an effective way to find cancer or pre-cancers before they become too big of an issue for treatments to be successful. If you missed your appointment last year due to COVID or are simply behind schedule, make an appointment with us to catch back up!

Blood Tests

One test that is used to indicate cancer is a CBC, or a complete blood count test. This test is useful because colorectal cancer often bleeds into the large intestine or rectum, causing people with the disease to become anemic. This test shows the number of red cells in the blood and can indicate whether or not bleeding may be occurring. A CEA test, or carcinoembryonic antigen test, is another test that is potentially useful in discovering colorectal cancer. A patient with high levels of CEA may indicate that a cancer has spread to other parts of the body. However, this isn’t exclusively used for colorectal cancer, as high levels of CEA may indicate other issues not related to cancer and can thus give a false cancer diagnosis. Lastly, a liver enzyme test may be useful as colorectal cancer, in its later stages, can spread to other organs like the liver or lungs. 


While other tests can suggest that colorectal cancer is present, a biopsy will give doctors the most confidence and accuracy when diagnosing colorectal cancer. A biopsy can be done during a colonoscopy (or surgery in some cases), and is the removal of small amounts of tissue for examination under a microscope. A pathologist, a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs, then analyzes the sample or samples taken from the patient. In some cases, a biopsy may be done during a CT scan or ultrasound in what is called a needle biopsy. A needle is guided into the tumor through the skin and a small sample is taken from the tumor.

Molecular Testing of the Tumor

A test that can be used to determine treatment options and to discover factors unique to the tumor involves the molecular testing of the tumor. These laboratory tests can help discover over issues as well, such as Lynch Syndrome, which is the most common cause of hereditary colorectal cancer. Molecular testing can also show if immunotherapy is an option for patients with metastatic disease, or where the cancer has spread to form tumors in other organs in the body.

CT Scan

In regards to colorectal cancer, a CT scan is used to determine whether or not the cancer has spread to other organs like the liver or lungs. A CT scan is useful because it gives a detailed, 3-dimensional image of the inside of the body using pictures taken by x-rays from different angles. A computer then combines these images to show whether or not there are any abnormalities on the organs. It can also be used to measure the size of a tumor.


Where a CT scan uses x-ray imaging, an MRI (magnetic resonance imaging) uses magnetic fields to produce detailed images of the body. Before the MRI, a special dye is given to make the image more clear for evaluation. This dye is called a contrast medium and can either be ingested via liquid or pill or it can be injected into a vein. An MRI is the most effective imaging test to show the size of the tumor and even discover where the colorectal cancer has grown. 


Ultrasounds, and specifically endorectal ultrasounds, are effective in discovering if or how much the cancer has spread. While this test can help with treatment options, it cannot accurately detect whether or not the nearby lymph nodes have been impacted. 


An x-ray, specifically of the chest, can help doctors find out if the cancer has spread to the lungs.

Positron Emission Tomography (PET) Scan 

While CT scans and MRIs are more common, a PET scan is an option doctors may use. For a PET scan, a slightly radioactive form of sugar is injected into the blood. This sugar then collects mainly in cancer cells. 

If you feel like you are showing potential symptoms of colorectal cancer, or would like to have a consultation to discuss your risk and preventative measures, schedule an appointment with us. Colorectal cancer is a disease you want to be proactive in preventing, as when you discover it may be the difference in whether or not you will be able to treat it effectively.