Colonoscopy plays an important role in preventing colorectal cancer because precancerous polyps can be detected and removed during the same exam when they are discovered. Colorectal cancer, often referred to as colon cancer, develops in the colon or the rectum (known as the large bowel or large intestine). The colon and rectum are parts of the digestive system, which is also called the gastrointestinal (GI) tract. The digestive system processes food for energy and eliminates solid waste. Colorectal cancer usually develops slowly over many years. Most colorectal cancer begins as a noncancerous (benign) adenoma or polyp (abnormal growth) that develops on the lining of the colon or rectum. Polyps can be removed to significantly reduce cancer risk. Colonoscopy is considered the gold standard of colorectal cancer screening methods for its ability to view the entire colon and both detect and remove polyps during the same procedure.
Colonoscopy lets your doctor examine the lining of your large intestine (colon) for abnormalities by inserting a thin flexible tube, as thick as your finger, into your anus and slowly advancing it into the rectum and colon. This instrument, called a colonoscope, has its own lens and light source and it allows your doctor to view images on a video monitor.
Colonoscopy may be recommended as a screening test for colorectal cancer, which is the third leading cause of cancer deaths in the U.S. Annually, approximately 150,000 new cases of colorectal cancer are diagnosed in the U.S. and nearly 50,000 people die from the disease. It is estimated that increased awareness and screening would save at least 30,000 lives each year.
Beginning at age 50, both men and women at average risk for developing colorectal cancer should have a colonoscopy every 10 years. People with risk factors or family history of colorectal cancer should talk with a gastroenterologist about screening sooner and find out how often they need to be screened. Individuals at any age with certain symptoms should speak with a physician. The following symptoms might indicate colorectal cancer: Blood in your stools, narrower than normal stools, unexplained abdominal pain, unexplained change in bowel habits, unexplained anemia, and unexplained weight loss. These symptoms may be caused by other benign diseases such as hemorrhoids, inflammation in the colon or irritable bowel syndrome. If you experience any of these symptoms for more than a few days, talk to a gastroenterologist.