Colon Cancer Prevention Screening

Colon cancer is the second leading cause of cancer-related deaths in the United States, causing approximately 30 percent of diagnosed patients to die from the condition each year. However, colon cancer, also called colorectal cancer, is highly treatable if diagnosed early.

While cancer experts recommend that male patients over 50 be screened for colon cancer each year, those who exhibit risk factors for it will also need frequent and regular screening. Some of the risk factors associated with colon cancer include:

  • age (Older patients are more likely to develop this condition.)
  • diet (Those who eat high-fat, low-fiber diets are at a higher risk of developing colon cancer.)
  • family history of this condition
  • lack of exercise
  • previous instances of colorectal cancer or colon polyps
  • race (African Americans and native Alaskans have a higher risk of developing colon cancer than Caucasians and American Indians.)
  • smoking.

Patients with any of these risk factors should talk to their doctors about setting up regular colon cancer screening tests.

In this section, we will outline the various types of screening tests that doctors use in the process of diagnosing colon cancer. Our articles will highlight the effectiveness and reliability of each screening test for colorectal cancer.

Digital Rectal Exams

During general physicals and regular gynecology checkups, both men and women will sometimes receive digital rectal exams (DREs) to check for any health problem affecting the organs and systems in the pelvis and lower belly area. To perform this test, doctors have men stand and bend forward at the waist while women lie on their backs with their feet resting in stirrups. Both male and female patients wear open-backed medical gowns during a DRE.

During rectal exam, the doctor lubricates one or two fingers and gently inserts them into the patient’s rectum. Once the finger is in, the doctor will start pressing on the patient’s belly with his free hand to help him feel the patient’s internal structures.

Health problems with the prostate, colon, uterus and ovaries may be detected during a digital rectal exam.

Fecal Occult Blood Test

Because colorectal cancer typically causes trace amounts of blood in bowel movements, doctors use the fecal occult blood test to detect it. The fecal occult blood test, one of the less invasive diagnostic procedures for colorectal cancer, requires that the doctor place a small amount of feces on a card treated with special chemicals.

Then, the doctor applies a distinct solution to the card. If the solution changes color, blood is present in the patient’s stool. At this point, doctors typically call for a more extensive examination of the patient’s colon, namely through a colonoscopy.

Researchers estimate that fecal occult blood tests reduce the chances of dying from colorectal cancer by as much as 30 percent. However, like other diagnostic tools, risks are associated with the fecal occult blood test.

Sigmoidoscopy and Colonoscopy

Both the sigmoidoscopy and colonoscopy are more invasive, yet more effective, procedures for determining whether or not patients suffer from tumors in their colons and rectums.

For a sigmoidoscopy, doctors require patients to completely clear their bowels, generally through the aid of laxatives and enemas. Once the bowels have been fully cleared out, doctors insert a narrow, lit tube up the rectum so that they can effective see if tumors or polyps exist. During this time, doctors may also take tissue samples of abnormal growths. Later, lab technicians can biopsy these tissues, checking to see if they are indeed cancerous.

Like a sigmoidoscopy, a colonoscopy is a diagnostic tool that requires doctors to use a small, lit tube to view possible cancerous growths in the patient’s colon and rectum. However, colonoscopies tend to be more effective than sigmoidoscopies in that they allow doctors to detect abnormalities that the sigmoidoscopy can’t.

Talk to your doctor about whether a sigmoidoscopy or a colonoscopy is right for you.


Fletcher, Robert H. MD (n.d.). Patient Information: Screening for Colon Cancer. Retrieved October 10, 2007 from the UpToDate Patient Information Web site: