(ABC News) -- Karen Witkus took the prescription, folded it up and tucked it in her wallet. She didn't want to think about the colonoscopy it would procure.
"I heard horror stories about it," said Witkus, 55, imagining the probing test and the gut-cleansing preparation it required. "I kept delaying and before you know it, it had been in my wallet for three years."
A colonoscopy is a procedure in which doctors view the inside of the colon with a small camera to spot and remove pre-cancerous growths called polyps before they turn into deadly tumors. It's the most sensitive of three colon cancer screening tests recommended for men and women over 50, but nearly half of all eligible adults skip the tests altogether, according to a 2009 study.
As a result, colorectal cancer remains the second leading cause of cancer death in the United States, killing more than 50,000 Americans annually, according to the U.S Centers for Disease Control and Prevention. Up to 60 percent of those deaths are preventable through screening, the agency says.
Dr. David Johnson, chief of gastroenterology at Eastern Virginia Medical School and past president of the American College of Gastroenterology says reasons for the low screening rates vary.
"One reason is that the test may not be covered by the patient's insurance," he said, alluding to insurance plans that are unaffected by the Affordable Care Act, which mandates coverage of colorectal cancer screening. Only 29 states and the District of Columbia have mandated that insurance plans cover colorectal cancer screening tests. "Another reason is that patients simply never have the conversation with their doctor."
Then there are people like Witkus, who despite having a referral and insurance coverage forgo the test out of fear. A colonoscopy requires that patients drink a gallon of bad-tasting laxative to cleanse the bowel, making polyps more visible. Patients miss up to two days of work – one for the pre-procedure doctor's visit and bowel prep and another for the procedure itself.
Although the benefits of a colonoscopy far outweigh the inconvenience and discomfort, doctors and researchers have nonetheless been searching for easier and more acceptable alternatives. One such test is currently under review by the U.S. Food and Drug Administration and Centers for Medicare and Medicaid Services. Developed by Exact Sciences, the stool-based screen detects changes in DNA as well as traces of blood that signal the presence of pre-cancerous polyps or cancers of the colon.
"I believe we have a significant opportunity to play a role in winning the battle against colon cancer," said Exact Sciences president and Chief Executive Officer Kevin Conroy, citing results from a recent clinical trial that suggest the stool-based test can detect 65 percent of polyps measuring 2 centimeters or more. "Colon cancer is the most preventable yet least prevented cancer. ... There is a significant need for something different."
Johnson, who was involved in the trial, agrees.
"Anything that brings more people into the screening pool, I'm all for," he said. He hopes the new test will play a "sizable role in increasing the options for screening," but cautions, "the best screening test is still the colonoscopy."
Colon Cancer Among 'Least Prevented,' Expert Says
When Witkus finally had her colonoscopy three years after getting the prescription. She was shocked to learn that she had colon cancer. Had she undergone the test at age 50, her cancer and subsequent surgery to remove 6 centimeters of bowel would have likely been avoided, her doctors told her.
Witkus did undergo screening with fecal occult blood testing two years before her colonoscopy and said she had no problem with the more convenient and less-invasive test. The test was negative but is known to miss the majority of polyps. She hopes that an equally accurate but less invasive test will one day be available, adding that the colonoscopy prep was the worst part.
While the new test is far from perfect, Johnson said he believes it could be refined to improve its sensitivity. But there are other unknowns, including the cost of the test and whether insurers will cover it. Approval by Medicare often triggers other insurance providers to cover the test, but if it's too expensive, the test might struggle to gain acceptance in an increasingly cost-conscious health care market. However, the potential to prevent cancer in more people and avoid costly treatment will certainly help its case. The cost of treating colon cancer exceeded $14 billion in 2010, according to the National Institutes of Health.
Thankfully doctors were able to remove Witkus' cancer before it was too late. But she knows that she was lucky.
"I talk to everybody I can now about colon cancer," she said. Her advice? "Definitely get the colonoscopy."