A colonoscopy is a procedure in which the doctor examines the rectum and colon to look for unusual growths or disease. Often if growths are found they can be removed during the examination.

The most important reason for this test is to screen for colorectal cancer, the third most common kind of cancer (besides skin and lung cancers) and the second leading cancer killer in the United States. In the United States, about 140,000 new cases were predicted for 2010 and about 50,000 people were expected to die of colorectal cancer; however, with improved screening the death rate has been decreasing.

The doctor, usually a gastroenterologist or surgeon, inserts a long, flexible tube with fiber optic lighting into the anus and then up through the rectum and colon. The doctor can view any growths, ulcers, or other abnormalities. In addition, small growths can be removed during the examination and sent to a laboratory for evaluation by a pathologist. Most patients are given sedation through an intravenous during the procedure.

You will be given detailed instructions before the procedure. This will usually include a period of 1-2 days before the test during which you will only be allowed to have clear liquids. The day before the test, you will also be instructed to clean out your colon using laxatives as prescribed by the doctor. You will be asked about your medical problems and medications and may be given special instructions regarding these issues.

• Prior colon or rectal cancer
• Prior adenomatous colorectal polyps or family history of these
• Ulcerative Colitis (you or family)
• Crohn’s disease (you or family)
• Close relative with colon or rectal cancer, especially before age 60
• Familial adenomatous polyposis (FAP) or variants
• Familial hereditary non-polyposis colon cancer (HNPCC)
• Ashkenazi Jewish or African American descent
• High fat diet, especially animal fat
• Obesity
• Sedentary lifestyle
• Smoking
• Alcohol
• Other possible factors: diabetes, night shift workers, prior testicular cancer, prior radiation for prostate cancer, cytomegalovirus