|
Gastroenterologist at Dreyer Medical Clinic – Mercy Campus and Fox Valley Villages
The American Cancer Society estimates that in 2008 there will be 108,070 new cases of colon cancer and 40,740 new cases of rectal cancer diagnosed. It is important to remember that most colorectal cancers can be prevented by simply having routine screenings. Many people fear these screenings and put them off as long as possible.
An experimental screening procedure, called virtual colonoscopy, has been well-publicized leaving many inquiring minds. As you have undoubtedly heard the pros of the procedure, including no need for sedation, it is worth your time to realize the disadvantages as well.
A virtual colonoscopy creates three-dimensional views of the colon. It is a method used to detect tumors and precancerous lesions (polyps) in the colon. A virtual colonoscopy relies on a CAT Scan to produce high-quality pictures of the colon. A radiologist uses special computer software to examine the images for polyps. An advantage of a virtual colonoscopy is that it eliminates the need to insert a long tube into the colon, or fill the colon with liquid barium.
However, a virtual colonoscopy has many disadvantages. A virtual colonoscopy does not show an accurate reflection of the colon. Polyps or growths less than five millimeters cannot be accurately detected. While a five millimeter polyp may not seem very big, it is not the size that matters. It is more important to know the type of the polyp. Cancerous polyps can be as small as five millimeters. In fact, one study found that 25% of all colon cancers using a virtual colonoscopy went undetected. For this reason, it is not recommended for screening purposes. By having a standard colonoscopy, polyps of all sizes can be detected and the physician will decide the necessary action to take.
Another disadvantage of a virtual colonoscopy is that it requires a catheter to be inserted into the rectum to inject air into the colon. This causes some abdominal discomfort. Also, a virtual colonoscopy uses x-rays to look inside the colon. Radiation was eliminated from standard colonoscopy procedures, due to the fact that several studies showed an increased risk of cancer.
More importantly, if a polyp is found during a virtual colonoscopy, a standard colonoscopy must be done to remove the polyp. It is very common for polyps to be found during a colonoscopy. If a polyp is found during a standard colonoscopy procedure, it can be removed immediately.
An important fact to know is that both, standard and virtual, require a colon cleanser to be taken prior to the procedure. This is usually the worst part of a standard colonoscopy. During a standard colonoscopy, a sedative is used and patients usually do not remember the procedure. Sedation is not used during a virtual colonoscopy.
|
