Americans have been inundated lately with conflicting messages about the value of popular screening tests for breast and prostate cancer. But there is one cancer for which experts agree more screening would do a lot of good.
Colon cancer, the No. 2 cancer killer in U.S. adults, can be curable if caught early. Yet nearly half of people over age 50 who could benefit from this screening are missing out on a potentially lifesaving check.
In Florida, a federally funded effort is trying a new tactic to change that dismal statistic. Working locally through the Moffitt Cancer Center and Research Institute in Tampa, state health officials are planning to use two different tests to try to reach the broadest audience possible.
Best known is the colonoscopy exam, made famous when Katie Couric received it on live television. The most common colon cancer screening, colonoscopy can prevent and detect cancer, but remains an expensive and invasive procedure, not to mention often dreaded for its unpleasant preparation.
Many people may not realize they have an alternative: the lower-tech stool test, used to screen for colon cancer at home for a fraction of the cost.
The scientific verdict remains out as to which exam is better. Both are effective if done right, say experts, who are emphasizing the need to align the testing options with patient preferences and limited resources.
"The right test is the one that is actually going to get done," said Carrie Klabunde, an epidemiologist in the division of cancer control and population sciences at the National Cancer Institute, who is watching Florida's experiment closely.
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Most colon cancer develops slowly, making it ideal to catch with screening. Over years, an abnormal growth on the intestinal lining can progress to a noncancerous growth called a polyp. A few polyps may become cancer over time, usually years.
About 5 percent of average-risk people age 50 in the United States develop colon cancer in their lifetimes, national estimates have found, and 2.5 percent die from it. Men are at slightly higher risk than women, and African-Americans are more likely to battle colon cancer than whites.
New cases of colorectal cancer could be reduced by as much as 90 percent if all polyps destined to become cancer could be identified through screening and removed, according to the U.S. Centers for Disease Control and Prevention, which is funding screening programs in nearly two dozen states including Florida.
"We know breast cancer is everywhere and lung cancer is high, but colorectal cancer somehow we are not as aware of," said Susan Fleming, a nurse overseeing cancer screening and education programs at the Florida Department of Health. "And it's preventable."
A problem is the colon cancer screening tests, which are notoriously unpleasant.
In colonoscopy, doctors use a thin, flexible tube attached to a small video camera to inspect the colon. Patients are sedated during the exam, which requires a day of advance preparation to cleanse the colon, often through laxatives and a clear, liquid diet.
Patients undergoing a colonoscopy must take at least a day off work and will need someone to drive them home. While rare, risks of the procedure are serious, including punctures to the colon wall and bleeding, which may require surgery to fix.
The upside to colonoscopy: If doctors find a polyp, it can be removed on the spot. Most patients, if clear, won't need another screening for 10 years.
"Colonoscopy is the test which will find the most polyps and the most cancers of any of the other available tests in a single screening situation," said Dr. James Allison, an adjunct investigator at Kaiser and professor of medicine emeritus at the University of California at San Francisco.
But he believes that many people would be just as well served, and perhaps even better off, by sticking with a simpler approach — the fecal occult blood test.
Known as FOBTs, these screening tests detect blood in the stool that can't be seen by the naked eye, but may signal the presence of a large polyp or cancer.
Using at-home kits, patients swab a small stool sample and send it to a lab for testing. Fecal blood screening is used to catch colon cancer at its earliest, most treatable stages.
The newer stool tests, called fecal immunochemical tests, are a marked improvement over the old-fashioned methods. Some can be completed with just one stool sample and don't require any special dietary restrictions.
But to work best, fecal blood tests must be taken every year.
"If patients will continue to do this, their benefit from screening will be exactly the same or maybe even better than with colonoscopy," Allison said. "Because every year, you have the chance to find something."
Ranging from around $5 to $50, fecal screening options are a lot cheaper than a colonoscopy, which can easily cost $1,500. If a stool test comes back positive, however, the patient still will need a colonoscopy.
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While colon cancer screening rates are rising, it still isn't as popular among patients as screening tests for other cancers. The uninsured are especially likely to be going unchecked.
To help close the gap, the CDC has launched a national colon cancer screening effort. Florida health officials received $850,000 for the first year of the five-year grant. Most of the money will be used to promote awareness, but some will provide free screenings in the Tampa Bay region, Miami and Gainesville to those who can't afford it.
Locally, Moffitt Cancer Center will be implementing the program, though its first-year budget is just $75,000 to $100,000.
In the next month, Moffitt plans to start offering free colonoscopies to 60 to 100 people, said Dr. David Shibata, chief of colorectal oncology at Moffitt. The number is so limited he was reluctant to publicize the program.
Patients will be selected in advance through local health care providers, he noted, and can't simply show up at Moffitt. In coming years, Moffitt hopes to expand the program by also offering one of the newer fecal blood tests.
"Obviously, that would have much more of a widespread impact," Shibata said of the less-expensive screening approach, which will be tested in the Miami area this year. "Instead of the hundreds of patients, it would be in the thousands of patients."
Still, experts caution, no cancer screening test is perfect.
Colonoscopy is only as good as the doctor doing the exam. For reasons not yet understood, emerging research suggests it may be better at protecting against cancers on the left side of the colon than on the right.
With fecal blood testing, patients should ask their physicians why they are recommending one testing kit over another and how extensively its results have been studied. A fecal blood test conducted by a doctor during a digital rectal exam in an office visit is not considered sufficient for screening.
But at least with colon cancer screening, experts generally agree the benefits outweigh the risks in adults ages 50 to 75.
"There is strong evidence to show that screening does reduce both mortality from colorectal cancer as well as the incidence of the disease," said Klabunde of the National Cancer Institute. "Where the controversy in colorectal cancer screening has come in is surrounding 'Is there a best test?' "
Letitia Stein can be reached at email@example.com or (813) 226-3322. For more health news, visit tampabay.com/health.