Colorectal cancer is the third most common cancer diagnosed among men and women in the United States. 

What is colorectal cancer?

Colorectal cancer is a type of cancer that begins in the rectum or colon. It can be named colon or rectal cancer, depending on where it started.

Most cases of colorectal cancer start with abnormal cell growths (also called polyps) in the inner lining of the colon or rectum. 

Not all polyps develop into cancer. The chance of polyp developing into cancer would depend on what type of polyp it is.

There are two main types of polyps – the hyperplastic and the adenomatous polyps. 

Hyperplastic polyps are the most common, benign cell growth whereas the adenomatous type is the one that can turn into cancer. Because of this adenomas are also considered as the pre-cancerous condition.

Other factors that can affect the polyps’ chance of becoming cancerous include the size (larger than 1 cm is found), number (more than 2 polyps are found), and if dysplasia takes place.

Dysplasia means there’s an area in a polyp or lining of the colon where the cells look abnormal. 

What are the symptoms of colorectal cancer?

In some cases, colorectal cancer may not cause symptoms right away. In the long run, it may cause any of the following:

  • Changes in bowel habits (e.g. diarrhea, constipation that may last for days)
  • Constant urge to have a bowel movement 
  • Blood in the stool
  • Rectal bleeding (having bright red blood)
  • Unexplained and unintended weight loss
  • Cramping or abdominal pain
  • Fatigue and weakness

How is colorectal cancer detected?

If colorectal cancer is suspected, the following tests may be used, on top of a thorough physical exam:

  • Colonoscopy
  • Biopsy
  • Magnetic resonance imaging (MRI)
  • Computed tomography scan (CAT or CT scan)
  • Positron emission tomography (PET) scan
  • Blood tests
  • Molecular testing of the tumor

Can colorectal cancer be prevented?

There are ways to lower your risk of colorectal cancer. This includes eating more whole food (e.g. vegetables, fruits, whole grains), not smoking, maintaining a healthy weight, getting regular exercise, and getting screened for colorectal cancer.

Screening for Colorectal Cancer

The U.S. Preventive Services Task Force recommends men and women age 50 to 75 be screened for colorectal cancer. 

Those who are at an increased risk of colorectal cancer (have a family history of it, have inflammatory bowel disease, smoker, have a low fiber diet, sedentary, and are obese) should see their doctor and talk about when to start the screening and how frequent.

The following are some of the tests used to detect colorectal cancer even before it occurs or progresses:

Stool Tests

  • Guaiac-based fecal occult blood test (gFOBT)

This test uses the chemical guaiac to detect the presence of blood in the stool.

  • Fecal immunochemical test (FIT)

It uses antibodies to detect blood in the stool.

  • FIT-DNA test

This test combines FIT with another test to determine altered DNA in the stool.

Flexible Sigmoidoscopy

Recommended every 5 or 10 years with FIT, flexible sigmoidoscopy uses a thin, flexible tube. This is inserted into the rectum to check for polyps or cancer inside the rectum.


Similar to flexible sigmoidoscopy, the long, thin, and flexible tube is used to check for polyps or cancer inside the rectum and the entire colon. This is recommended every 10 years.

CT or Virtual Colonography

This test is recommended every 5 years. It uses computers and X-rays to produce images of the entire colon.

There is no single best screening test. The type of test that’s suitable for you would depend on several factors. Talking to a specialist can help you determine the most suitable test for you.

Premier Surgical Associates of Knoxville and Cleveland, TN have board-certified surgeons who are experienced in diagnosing and treating colorectal cancer. To request an appointment with one of our specialists, visit  or call the main Premier Surgical phone line at (865) 306-5775.


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