Frequently Asked Questions About Colorectal Cancer

Medically Reviewed by Nayana Ambardekar, MD on August 11, 2021
6 min read

Print out these questions and answers to discuss with your doctor.

Because you don't have a family history of colorectal cancer or polyps, you are considered at average risk for colorectal cancer. Men with average risk should begin prevention examinations at age 50. The recommended screening tests to detect early-stage lesions and polyps for men at average risk include:

  • Fecal occult blood test This test examines the stool for blood not easily noticed by the naked eye. For men at average risk of colorectal cancer, this test should be performed every year starting at age 50.
  • Flexible sigmoidoscopy Flexible sigmoidoscopy is a routine outpatient procedure in which a physician uses a sigmoidoscope (a long, flexible instrument about a 1/2-inch in diameter) to view the lining of the rectum and the lower third of the colon (called the sigmoid and descending colon). This test is usually done every 5 years and can be used in combination with the yearly fecal occult blood test.
  • Colonoscopy This is an outpatient procedure in which the rectum and the inside of the entire colon are examined. During a colonoscopy, a doctor uses a long, flexible instrument about a 1/2-inch in diameter to view the lining of the colon. This test is recommended every 10 years, starting at age 50.

Other screening tests that are not as commonly used include:

  • Air contrast barium enemaSometimes, a doctor will use a test called air contrast barium enema. This test is an X-ray examination of the entire colon and rectum in which barium and air are introduced gradually into the colon by a rectal tube to improve visualization. Doctors typically recommend this test (sometimes in combination with flexible sigmoidoscopy) every five years, starting at age 50.
  • Virtual Colonoscopy This test uses a CT scanner to make images of the inside of the colon and rectum. Though it appears to be as accurate as a colonoscopy, studies are underway to see how this test compares to the other recommended screening tools.
  • Fecal Immunochemical Test (FIT)  This test checks for blood protein in a stool sample that might indicate colorectal cancer.  It is performed every year starting at age 50.
  • Stool DNA test  This is another stool sample test that checks for gene changes in colorectal cancer cells or polyps that might indicate colorectal cancer.  The American Cancer Society recommends this test be performed every 3 years.

Ask you doctor which of these tests or combination of tests is right for you.


The earliest sign of colorectal cancer may be bleeding. But if you find blood in your stool, don't panic. A number of different conditions can cause bleeding, not just colon cancer. If you find blood in your stool, see your doctor so that a correct diagnosis can be made and proper treatment received.

Other symptoms to look out for if you suspect colon cancer include:

  • Change in bowel habits (constipation or diarrhea)
  • Unusual stomach or gas pains
  • Very narrow stool
  • A feeling that the bowel has not emptied completely after passing stool
  • Unexplained weight loss
  • Fatigue

An adenoma is a benign, or non-cancerous polyp or growth in the lining of the large intestine. Adenomas are considered to be precursors of colon and rectal cancer.

Cancers of the colon and rectum can begin as an adenoma, but few adenomas (only 1 or 2 out of 100) ever become malignant (cancerous). This process takes several years. When polyps are discovered during an examination of the colon (such as the colonoscopy), doctors sometimes find it hard to tell which are pre-cancerous and which are not. Even among adenomas, it is impossible to tell which ones will become malignant, although larger adenomas are at a higher risk for becoming malignant. For this reason, all polyps in the colon and rectum are removed.

There has been substantial debate over whether diet affects a person's risk of colon cancer. It is believed that fiber is important to reduce colon cancer risk, although some studies have shown that a high-fiber diet really doesn't make a difference. However, diets rich in fat and cholesterol are associated with an increased risk of colon cancer.

Still, most scientists agree that people should continue to add fiber to their diets, as fiber-rich foods are an important source of nutrients and help prevent many other serious conditions, like heart disease. Research also shows that a high-fiber diet may help lower blood pressure, improve blood sugar, combat overeating, and help prevent other gastrointestinal conditions like diverticulosis (outpouchings of the lining of the intestine that are prone to bleeding and infection), constipation, and maybe even stomach and esophageal cancers.

Keep in mind that the best way to prevent colon cancer is to keep active, eat a balanced diet, maintain your ideal body weight, and schedule polyp screenings regularly after age 50, or earlier if you have a family history of colon cancer.

Cancer-related fatigue is one of the most common side effects of cancer and its treatment. The exact reason for this fatigue is unknown, but it may be related to the disease process or its treatments.

To combat fatigue, have your husband follow these suggestions:

  • Evaluate your energy level. Keep a diary for one week to identify the time of day when you are either most fatigued or have the most energy. Note what you think may be contributing factors.
  • Be alert to your personal warning signs of fatigue, such as difficulty in concentrating, body aches and pains, and feelings of exhaustion.
  • Conserve energy by planning ahead and organizing your work, scheduling rest, pacing yourself, practicing proper body mechanics, and by prioritizing and delegating your activities.
  • Maintain good nutrition. Ask a dietitian for tips on eating healthy during your cancer treatments.
  • Exercise. Regular, moderate exercise can often decrease feelings of fatigue, help you stay active, and increase your energy. Even during cancer therapy, it is often possible to continue exercising. Check with your doctor before increasing your activity level.
  • Manage stress by adjusting your expectations, practicing relaxation techniques, and participating in activities that divert your attention away from fatigue.
  • Talk to your doctors. Although cancer-related fatigue is a common, and often expected, side effect of cancer and its treatments, you should feel free to mention your concerns to your doctors. There are times when fatigue may be a clue to an underlying medical problem. Other times, there may be medical interventions to assist in controlling some of the causes of fatigue. Finally, there may be suggestions that are more specific to your situation that would help in combating your fatigue.