How Do I Know If I Have Colorectal Cancer?

The size of the colorectal cancer and how far it has spread are the best indicators for survival. Therefore, early detection is key. Beginning at age 50, the American Cancer Society recommends the following screening guidelines for both men and women without significant risk factors or symptoms:

A yearly fecal occult blood test to check stool for blood.
Every five years a double-contrast barium enema where the area is examined with an intensive x-ray to look for abnormalities.
Every 10 years, a colonoscopy where the doctor uses a long, lighted tube (called a “colonoscope”) to look inside the rectum and the entire colon for polyps or other abnormal areas that may be cancerous.

People who have any of the colorectal cancer risk should consult with a physician about more frequent screening.

Often there are no obvious signs of colorectal cancer, but some symptoms can include:

Change in bowel frequency, such as alternating episodes of diarrhea and constipation.
Bloody bowel movements or rectal bleeding.
General abdominal discomfort.
Unexplained weight loss.
Chronic fatigue.
Bloating.
Unexplained anemia.

There are several tests physicians can use to further the diagnostic process and look for colorectal cancer. In addition to the screening tests described above, these include:

Digital rectal exam (DRE) - to evaluate the rectum for abnormal tissues.
Sigmoidoscopy - a procedure in which the physician uses a thin, lighted tube to look inside the rectum and lower portion of the colon (called the sigmoid) for polyps or other abnormalities.
Colonoscopy - which is performed like the sigmoidoscopy, but allows the physician to see the entire colon.
CT, MRI or PET scan – to determine if the cancer has spread.

As with other cancers, the only way to know for sure is with a biopsy – a procedure in which a sample of the tumor is sent to the lab to be examined under a microscope. This sample is typically taken during the sigmoidoscopy or colonoscopy.