Understand your diagnosis and treatment options with genetic testing

Colon cancer

Genetic testing gives you and your physician tools to personalize your treatment specific to your colon cancer. In addition to changing how you may treat your colon cancer; your results may indicate you are at an increased risk for additional cancers. Having this information will empower you and your physician to be proactive in your treatment decisions and future screenings. 

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Myriad Oncology's Tests for Colon Cancer and What Answers They Provide:

Hereditary cancer testing

myRisk genetic testing

Myriad myRisk® is a gene panel that helps identify your options for treatment, your risk of additional cancers, and if any close family members may be at an elevated risk of developing cancer.

Hereditary cancer risk associated with colon cancer

1 in 3 people who develop colorectal cancer have other family members who have had it.1 This history could suggest a hereditary factor – a genetic change or mutation being passed down in families. Inherited genetic mutations account for up to 10% of all colon cancers.2 By knowing your genetic risk factors, your doctor can better diagnose and treat your colon cancer and prevent future colon cancers in your family.

If your cancer was caused by a mutation, your children and siblings have a 50% chance of having that same mutation. Genetic testing helps identify these mutations, and it has been found that individuals with an identified hereditary cancer syndrome have up to an 82% risk of developing colon cancer by the time they are 70.3 They are also at a much higher risk of developing other cancers.

To see if genetic testing will benefit you, take The Hereditary Cancer Quiz. It is time to take control of your health.

What is Colon Cancer?4

Colon cancer, sometimes called colorectal cancer, is a cancer that affects the colon and rectum. It occurs when abnormal cells within this tissue grow out of control. Most colorectal cancers start as a growth on the inner lining of the colon or rectum. These growths are called polyps.

Some types of polyps can change into cancer over time, but not all polyps become cancer. The chance of a polyp growing into cancer depends on the polyp type. Adenocarcinomas make up about 96% of colorectal cancers, and these cancerous polyps start in cells that make mucus to lubricate the inside of the colon and rectum. People who have a hereditary condition called Polyposis Syndrome may be at higher risk for polyps.

Two types of polyps:

  • Adenomatous polyps: These polyps sometimes change into cancer and are occasionally called pre-cancerous.
  • Hyperplastic polyps and inflammatory polyps: These polyps are more common and not usually pre-cancerous.

Colon Cancer Signs and Symptoms4

Common signs and symptoms of colon cancer:

  • A change in bowel habits, such as diarrhea, constipation, or narrowing of the stool that lasts for more than a few days
  • A feeling that you need to have a bowel movement that’s not relieved by having one
  • Rectal bleeding with bright red blood
  • Blood in the stool, which may make the stool look dark
  • Cramping or abdominal pain
  • Weakness and fatigue
  • Unintended weight loss

Some of these symptoms can be caused by other conditions, such as infection, hemorrhoids, or irritable bowel syndrome. Consult your healthcare professional if you experience any of these prolonged symptoms. Consult your healthcare professional if you experience any of these prolonged symptoms.

Colon Cancer Diagnosis and Staging Colon Cancer Screening4: Doctors may ask for a blood test or stool sample to see if your colon is bleeding through your stool. They may also perform a digital rectal exam looking for signs of colon or rectal cancer. The last step may be a colonoscopy. A colonoscopy is a process where a small camera is inserted into your colon, which may lead to a biopsy. This is when tissue is removed and studied. Once a diagnosis has been confirmed, your healthcare professional will determine if it has spread. This is called staging.

Staging4: The staging system most often used for colorectal cancer is the American Joint Committee on Cancer (AJCC) TNM system, which is based on 3 key pieces of information:
  • The extent (size) of the tumor (T): How far has the cancer grown into the wall of the colon or rectum?
  • The spread to nearby lymph nodes (N): Has the cancer spread to nearby lymph nodes?
  • The spread (metastasis) to distant sites (M): Has the cancer spread to distant lymph nodes or distant organs such as the liver or lungs?

Colon Cancer Treatment Options4

The most common treatment for colon cancer is surgery, but other treatments may include chemotherapy or radiation to attack any remaining cancer in your body. 

Colon surgery requires a clean and empty colon. You may be put on a special diet before surgery or use laxative drinks and enemas to remove any stool in your colon. There are varying degrees of colon cancer surgery.


This is a surgery where just the polyps are removed. This is done by passing a wire loop through the colon to cut polyps from the colon wall using an electric current.


If only part of the colon is removed, it’s called a hemicolectomy or partial colectomy. A part of the diseased colon is removed, and the segments are reattached.

Total colectomy

If all of the colon is surgically removed, it’s called a total colectomy. A total colectomy is only used in the most extreme cases.

When used along with other cancer-fighting treatments, surgery can be effective. Talk with your doctor about all the risks and benefits of each treatment and possible side effects.


1. https://www.cancer.org/cancer/colon-rectal-cancer/causes-risks-prevention/risk-factors.html

2. Yurgelun M, et al. Prevalence of germline cancer susceptibility gene mutations in a clinic-based series of colorectal cancer patients. Presented at ASCO 2016 Jun 7.

3. Lynch HT, et al. Hereditary colorectal cancer. N Engl J Med. 2003 Mar 6;348(10):919-932.

4. American Cancer Society. Cancer Facts and Figures 2020. Atlanta, Ga: American Cancer Society; 2020.

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