Not a fun thing, but it's a proven life-saver
If you knew of a cancer-screening test that, for most patients, is fairly painless, low-risk and highly effective, would you take it? How about if you were told that the same test requires consuming about a gallon of liquid, proximity to a bathroom as your bowels empty out and having someone insert a long tube into a very private part of your anatomy?
We know what you're thinking: ew.
Therein lies one of the challenges of colonoscopy, a health test that is much-dreaded by some and normally recommended for adults starting at age 50. It might be a steadfast ally in the battle against cancer, but it can't do a darned thing if people refuse to show up for the appointment - or don't realize that they should make the appointment in the first place.
Colon cancer, also called colorectal cancer, is the second leading cause of cancer-related death in the United States, but it's estimated that only 60 percent of U.S. patients who should have a colonoscopy actually have one. That's not just due to the unappealing nature of the test and its associated preparation, however. The missing 40 percent can also be attributed to inadequate awareness of the test, despite many primary care doctors' diligent efforts to spread the word, says Richard C. Dai, M.D., a gastroenterologist at St. Joseph Hospital in Nashua.
"It's very common," Dai says, to "see patients that are 60 or 70 years old [who] for the first time are having a colonoscopy. When I ask 'Why did you wait this long to have a colonoscopy,' they say they didn't know they were supposed to have it."
What's it like?
A colonoscopy allows a doctor to check the lining of your colon, or large intestine, which is the last portion of your digestive tract, for abnormalities. When used for colon cancer screening, the goal of a colonoscopy is to find polyps, or growths, and remove them before they become cancerous. During the procedure, which is typically 20-30 minutes long, a finger-width, lighted, flexible tube with a tiny camera at the end is inserted into the rectum and guided through the colon, allowing the doctor to see what's inside.
Although some patients might experience discomfort, most say they are surprised at how easy and painless the procedure is, and most do well with very little sedation, Dai says.
Prepare to purge
In fact, those who have experienced a colonoscopy almost always grumble more about the bowel preparation than the test itself, but proper bowel preparation is an essential component of colonoscopy because it voids the colon of fluids and solids, allowing the physician to see the colon lining clearly. The day before the procedure, the patient must subsist on a clear liquid diet, drink substantial amounts of fluid and purge with laxatives. Anything less than a squeaky-clean colon on the day of the test could compromise colonoscopy results by obscuring the physician's view, leading to missed polyps.
A virtual misnomer
"Virtual" colonoscopy, CT colonography or CTC all refer to the same thing: a promising new way of performing colonoscopy that relies on x-rays and computerized images. (CT stands for computerized tomography.) CTC-related technology is still developing, and the technique is not commonly used in New Hampshire or even in the country, but some experts believe it could play a big role in colon cancer screening in the future.
CTC is faster, less invasive and even safer than traditional colonoscopy, which is very low-risk. But if you're hoping CTC will be something akin to a chest x-ray, you might be disappointed. Indeed, calling CTC "virtual" can be misleading, says Lynn Butterly, M.D., director of Colorectal Cancer Screening at Dartmouth-Hitchcock Medical Center and the Norris Cotton Cancer Center. Bowel prep is still necessary, and although CTC eliminates the need for a tube to be snaked through the colon, air must be pumped in to allow the physician a good view of the colon lining, Butterly says, and that can cause a crampy or bloated feeling.
Aspects of CTC remain to be sorted out, including whether it is cost-effective, particularly since polyp removal still requires a traditional colonoscopy, Butterly says. Also, there is concern about patient willingness to tolerate the discomfort created by the pumped-in air, although the cramps and bloating are short-lived. Researchers continue to investigate the risk of cumulative CTC radiation exposure, and some are not convinced of CTC's effectiveness as a tool for finding polyps, as studies have shown conflicting results.
Nonetheless, CTC continues to evolve and improve. Radiologists are even working on techniques that would allow colon stool and liquids to be "tagged" or electronically removed from the CTC image the doctor sees, Butterly says. If such a method can be developed, patients wouldn't need to undergo the usual bowel preparation for CTC - a huge advantage. But Butterly warns that some bowel prep would still be necessary. Patients would no longer need "a cathartic prep that makes them go to the bathroom," she says, but would need to drink a large amount of the tagging agent.
The big picture: prevention
The aim of most cancer screening tests is early detection, but colon screening really is more about prevention, Butterly says, noting that colon cancer is one of a few cancers that can be prevented. "With most cancers, you either have it or you don't, and the name of the game is detecting it early" to improve your chances of survival, she says. In contrast, most colon cancer starts off as a polyp. Polyps that become cancerous take about five to 10 years to do so, but any polyp that is discovered and removed through colonoscopy never has a chance to become cancer.
Through colonoscopy screenings, doctors find cancer only about .1 percent of the time in people who begin screening at the recommended age, Butterly says. "But what we do find 40 percent of the time or more are polyps, and if we get rid of them, that greatly reduces your chances of getting colorectal cancer. It is that chance for prevention of cancer that makes such a strong case for colorectal cancer screening."
This article appears in the March 2009 issue of New Hampshire Magazine