For those of you nearing 50, you probably know it’s almost time for that very effective screening test for colon cancer, the colonoscopy. If horror stories of the “cleansing” preparation have turned you off, then you’ll be happy to hear about the new laxative-free colonoscopy that’s in the pipeline (no pun intended!).
It’s called a laxative-free computed tomographic colonography (CTC) or virtual colonoscopy. Rather than cleansing the colon the day before the procedure, patients will ingest a small amount of contrast agent a few times a day over 2 days with snacks. The volume of contrast agent is about the size of a ketchup packet. We can handle that, right?
The procedure is then similar to a virtual colonoscopy, in which x-rays create images of the colon and a computer combines all the images to form 3-D pictures of the colon. There’s no scope involved. Sigh.
“We observed with this laxative-free version we could identify patients who had one or more polyps 1 centimeter or greater in size and we could do that with a performance that was very similar to optical (traditional) colonoscopy and in a range that many people would consider acceptable for screening,” says study author Dr. Michael Zalis, director of CT Colonography at Massachusetts General Hospital. “We could detect 91% of these larger lesions in our study, while optical colonoscopy detected 95%.”
The fact that the laxative-free test was less successful finding growths smaller than 1 centimeter may not be cause for concern. According to Zalis, smaller lesions are clinically less important. “We can’t ignore them, but we know that the most important lesions to get are the advanced adenomas and 90% of them are 1 centimeter or larger.”
Researchers hope that people will find this method of test preparation more pleasant than the conventional cleansing route and will get screened, which only needs to happen every 10 years (if no polyps are found).
The study of 605 adults who had this type of colonoscopy was published yesterday in the Annals of Internal Medicine. Results from this small study will need to be validated by a larger study.