Colonoscopy is a commonly performed procedure used to diagnose and treat disorders of the colon. It is frequently used to screen the adult population over age 40 for pre-cancerous polyps or asymptomatic cancers (that means without an obvious sign or symptom of the disease). Colon cancer is the second leading cause of cancer deaths in the U.S. It occurs equally in men and women. It is believed that the detection and removal of pre-cancerous polyps will prevent colon cancer and the detection and removal of early asymptomatic colon cancers will reduce mortality from this disease. Colonoscopy is performed with an appx 165 cm (75-inch) long, flexible video fiberoptic scope. It is inserted into the rectum and passed under direct visualization to the cecum and sometimes into the terminal ileum (the end of the small intestine). There are one or two channels in the colonoscope to allow for the introduction or removal of air into the colon and for the introduction of biopsy forceps or other instruments to remove polyps. The procedure typically takes 15-30 minutes and is usually performed under some form of intravenous sedation.
The colon is a long, winding organ and can be examined in its entire length in the majority of cases. However, in a small percent of patients, examination of the entire colon cannot be achieved due to repeated bends and curves of the colon or previous abdominal surgery. If the colon prep is poor, a repeat procedure with a better prep may be necessary.
If the lining of the colon is abnormal, a biopsy may be taken to further assess abnormality. If any polyps are discovered, they will usually be biopsied and/or removed and sent to the pathology lab for analysis. Large polyps are removed by a technique called snare polypectomy. A wire loop is passed through the colonoscope and around the base of the polyp. A cutting/cauterizing electrical current is sent through the wire, which severs the polyp and stops any significant bleeding. If the nature and number of polyps prevents safe removal, your doctor might either repeat the procedure or refer you to a surgeon. No pain is experienced during a polypectomy or biopsy of the colon. If the physician performing colonoscopy finds a polyp and determines it can be safely removed, it will be removed and sent to a pathology lab for analysis to check for the presence of abnormalities such as cancers. Such removal is normal and is accepted as the best practice. If you do not wish to have the polyps removed, please do not sign this consent and discuss with your gastroenterologist.
Since sedation is administered, it will be necessary to someone drive the patient home after the procedure. Even if the patient intends to take a taxi home, someone must accompany him/her in the taxi. Patient may not lift weights or resume any stringent physical activity for one week after the procedure. If patient experiences any abnormal pain or fever or chills or are unable to pass gas, please contact your gastroenterologist immediately. If you are unable to contact please go to the nearest emergency room and after you have been stabilized have the ER doctor contact your gastroenterologist.
Alternative procedures that are also used to diagnose colonic disorders are “virtual colonoscopy” (a special CT scan of the colon) and barium enema. These are performed by a radiologist, expose you to small amounts of radiation, require a cleansing prep, and can frequently be uncomfortable due to the injection of air or barium. If there are any findings on these x-ray procedures, the patient may be then be referred for a colonoscopy, meaning the patient may have to undergo two procedures. Cologuard is a relatively newly available diagnostic tool where you send in a stool sample to a lab where they look for signs of colon cancer. As with virtual colonoscopy, if this test is positive you need to go through colonoscopy.
Although colonoscopy is the “gold standard” procedure to diagnose and potentially treat colon polyps, colon cancers, and other conditions of the colon, it is not a perfect test. There is a small miss rate of significant findings with this procedure. Tumors that hide behind the stomach lining as well as certain rare flat polyps may be hard to visualize. Very large polyps might have to be removed by a surgeon. When the preparation is not perfect there is a chance for lesions to be missed.
Colonoscopy is a safe procedure, however, there are risks associated with it. While we have discussed these and possibly others during your consultation, we would like you to have a list so that you may ask questions if you are still concerned. It is important that every patient be made aware of possible outcomes that may include, but are not limited to:
- Perforation (puncturing) of the colon: This is the most serious risk of the procedure. The symptoms of perforation are severe abdominal pain after the procedure. The diagnosis is made by a plain x-ray or CT scan of the abdomen. Small perforations can be treated by hospitalization and watchful waiting, but sometimes urgent or semi-urgent surgeries are needed to close the perforation. Depending on the nature and scope of the perforation temporary or permanent colostomy bag might become necessary. All surgeries carry the risk of bleeding, unforeseen complications, and, mortality.
- Colonic bleeding if a polyp is removed: Bleeding can occur immediately after the procedure or be delayed for hours or days. After a large polyp is removed it is usually not advisable to resume ingestion of aspirin products or anti-inflammatory medications for at least 1 week. Acetamonophen (Tylenol®) can be used instead.
- Over-sedation during the procedure: Sedation can depress respiration and blood pressure. Patients are carefully monitored during the procedure and sedation is administered slowly to prevent complications. Even though not common, anesthesia carries the risk of mortality and other unforeseen complications such as aspirations, cardiac arrest, respiratory failure and IV infection and thrombosis.
- Other risks: Injury to other organs such as spleen; hospital borne infections, allergic reactions, abdominal hematoma requiring surgery or radiological intervention are rare but could happen