What to expect with a colonoscopy, from prep to results

Colon cancer is the third most common cancer and the second-leading cause of cancer death in the United States. More than 140,000 new cases are diagnosed each year. Screening colonoscopies prevent cancer death by allowing doctors to detect and remove polyps before they grow and become cancerous.

Most people should have their first colonoscopy at the age of 50. However, if you have a higher risk, such as a family history of colon cancer, you may need to be screened earlier. Your doctor can tell you when and how often you should be screened.

Preparation of the bowel is an extremely important part of the colonoscopy. This process begins the day before your exam and is designed to empty your colon completely, so that your gastroenterologist can have the clearest view available to see tiny formations. Many patients say this is the most challenging part of the entire test, because it requires a day-long liquid diet, as well as taking laxatives that cause diarrhea.

These two components ensure that you empty your bowel completely, but these also can be unpleasant to some. As a result, planning to be close to a toilet during this stage is essential.

On your screening day, you may have an initial consultation with the gastroenterologist. For your exam, you will change into a gown and will be asked to lay on your side on the exam table. The colon screening procedure takes about 30-to-60 minutes, during which time you receive medicine through an IV to keep you in a deep sleep.

Once you are resting, the doctor inserts a flexible tube with a light source and a tiny video camera at its tip into your colon. The camera sends images from inside your colon to a screen that can be viewed by your doctor. The doctor can insert micro-instruments through the scope to remove any polyps, or to take tissue samples for additional study.

When the exam is complete, your medication is reduced, and you wake up.

You’ll need some time to recover from the sleeping medication, and you are required to have someone available to drive you home, as you should not drive or go back to work for the rest of the day.

Results from your colonoscopy are available immediately. And, if a biopsy is taken, those results are typically back within a few days.

Major complications from a colonoscopy are very uncommon, and only about 5 percent of patients report some mild abdominal cramping, similar to having a bowel movement, following the procedure. You will likely experience some gas, which can be alleviated with walking.

If your doctor has taken tissue for a biopsy, you may be instructed to follow a special diet.

While nothing is as effective as a colonoscopy for colon cancer screening, any screening is better than no screening at all. One option that is sometimes used as an alternative is called fecal occult blood testing.

This yearly screening is performed at home, using a test kit. A small stool sample is provided to the doctor and tested for blood, which can be a marker for cancer.

Your doctor can provide guidance regarding which screening test is best for you.

Kumar, of the Digestive Disease Center, at UPMC Susquehanna is certified in internal medicine and gastroenterology.