Two years ago, when I turned 50, my doctor and I had a chat about colon cancer screening. It went something like this:

Doc: "It's time for a colonoscopy."
Me: "I'm not sure I want one."
Doc (eyebrows raised): "You don't think you could get colon cancer?"
Me: "It's not that. I'm just not sure I want a colonoscopy."

In the end, we compromised. I agreed to see a gastroenterologist to discuss the possibility of going through with the procedure. Which, it turns out, is like talking with a salesman about the possibility of buying a car when you're already in the showroom, hands on the wheel.

Rare is the doctor who doesn't wholeheartedly believe that colonoscopy is the best means of early detection. But there are a few out there, including no less an expert than Richard Wender, MD, chief cancer control officer at the American Cancer Society. "Colonoscopy is a wonderful screening test," Wender says. "But I can confidently state it's not the gold standard." He notes that he isn't against the procedure; it's just that research shows that as a screening tool, it isn't substantially more effective at preventing cancer deaths than other options.

What are those options? One, the fecal immunochemical test (FIT), checks for hemoglobin in your stool (yes, you have to send in a swab of your poop), which can be a sign of cancer. The other, sigmoidoscopy, is similar to colonoscopy but is less invasive and doesn't scan the whole intestine. The U.S. Preventive Services Task Force, an independent panel that evaluates medical evidence, put FIT and sigmoidoscopy (when coupled with FIT) on approximately equal footing with colonoscopy in terms of efficacy. According to the task force's recent research, all three screening strategies have about the same benefit when properly used: averting an estimated 22 to 24 deaths from colorectal cancer for every 1,000 people screened. Yet among Americans ages 50 to 75 who were screened in 2012, 61 percent had colonoscopies, while 10 percent or less used fecal blood tests or sigmoidoscopies.

There are many reasons for the disparity. Colonoscopy, which used a flexible endoscope that can wind its way through the twists and turns of the large intestine, caught on as a screening tool in the 1990s. A camera mounted at the end of the scope allows a doctor to see polyps, small growths that in some cases lead to cancer and, with the help of a wire loop, can be removed on the spot. "No other screening tool rivals colonoscopy in terms of both accuracy and the ability to remove polyps," says gastoenterologist Michael Kirsch, MD, author of the blog MD Whistleblower. Medicare started covering the procedure in 1998. In 2000, when Katie Couric filmed her colonoscopy for television, its popularity soared.

But the test's overwhelming dominance comes at a cost. It is by far the most expensive way to screen: The International Federation of Health Plans 2012 Comparative Price Report found that in the U.S., the average price, not including anesthesia, was almost $1,200, and a New York Times investigation found patients who were billed much more, including one whose balance (which included a polyp removal) approached $20,000. By contrast, FIT can cost around $20. "There is no question that a huge proportion of the work gastroenterologists do is colonoscopy," says Richard Hoffman, MD, director of the Division of General Internal Medicine at the University of Iowa Carver College of Medicine. Hoffman points out that the American College of Gastroenterology favors the procedure. "I find it disconcerting that a professional organization is saying 'we prefer colonoscopy screening'—a recommendation based on their expert opinion—when their membership is going to benefit financially." In a statement to O, an organization spokesman said the preference for colonoscopy is not a conflict of interest, but based on the test's ability to prevent colon cancer (with polyp removal), not just detect it.

Yet emphasizing colonoscopy could discourage some—people in jobs that don't easily allow for time off (the average procedure, which requires sedation, takes 20 minutes to an hour), people who can't afford the insurance co-pays or lack insurance altogether, people just leery of the prep and procedure—from being tested at all, Wender says. He and other cancer experts would like to see more informed discussion of all methods. A 2013 CDC report noted that overall colon cancer screening rates (the lowest among recommended cancer screenings) would likely be higher if patients had access to all recommended screening tests; unfortunately, many primary care providers, so convinced of colonoscopy's supposed superiority, don't even suggest the other tests to patients.

The good news: More approaches are in the pipeline. One of them, called Cologuard, was developed in collaboration with mayo Clinic researchers and approved by the FDA in 2014. It's similar to FIT, but in an effort to improve sensitivity, it also looks for certain DNA mutations associated with cancerous and precancerous colorectal growths. A clinical trial reported in The New England Journal of Medicine found that Cologuard's detection rate bested FIT's. Another promising method being researched is virtual colonoscopy, which relies on CT or MRI scans to look at the colon.

Someday I might get one of those new tests, but for now—with my work, children to tend to, a busy husband, and the difficulty of sacrificing up to two days of our hectic lives—I'll stick to the annual FIT. I've changed enough diapers not to be squeamish if I have to swab my own poop once a year. And who knows—at some point I may even have a colonoscopy. But the choice will be mine. KEEP READING: How to decide which test is right for you

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