Benjamin Franklin once said, "An ounce of prevention is worth a pound of cure." He was talking about preventing fires in 18th century Philadelphia, but you can say the same today about certain diseases – including colorectal cancer.
The American Cancer Society(ACS) reports more than 150,000 diagnosed cases in the U.S. each year, leading to more than 50,000 deaths. The good news is survival rates improve with early detection.
Even better, you can prevent cancer before it develops by finding and removing polyps early. That's why regular screening is important, and with the rise in popularity of at-home testing, it's important to know what works best.
The ACS recommends that people at average risk of colorectal cancer start regular screening at age 45. The three most common forms of screening are a colonoscopy, a fecal immunochemical test (FIT), and Cologuard®, an at-home non-invasive fecal DNA test.
All three can detect colorectal cancer, are generally covered by most insurance plans, and require a prescription from your doctor. But to determine which test is right for you, it's important to understand the benefits and limitations of each.
Fecal Immunochemical Test
You can do FIT testing at home by collecting a stool sample and sending it back to a lab, where antibodies pick up the presence of blood in your stool This can indicate the presence of cancerous tumors in the colon.
A FIT test is 79 percent accurate at detecting colorectal cancer. Experts recommend FIT testing every year beyond age 45. A positive result from a FIT test still requires a colonoscopy to confirm the diagnosis.
"All it does is detect blood," says Janice Rafferty, MD, the Chief of Colon and Rectal Surgery and Director of Oncology Services at The Christ Hospital Health Network.
"It could detect blood in your stool from biting your cheek, or taking an iron pill, or eating an exceedingly rare steak. But you know what you get with a positive test? A colonoscopy."
Cologuard Fecal DNA Test
Like FIT testing, you can test with Cologuard at home by taking a stool sample and sending it back to a lab, which tests for the presence of blood in the stool. However, it also detects DNA markers in the stool that could indicate the presence of colorectal cancer.
Cologuard detects 92 percent of existing cancer and 50 percent of precancerous polyps. It also has a 13 percent rate of false positive tests. Experts recommend testing with Cologuard every three years beyond age 45. Like FIT testing, a positive result requires a colonoscopy to confirm the diagnosis.
Many prefer home testing such as Cologuard over colonoscopies because they are non-invasive, convenient, and don't require the unpleasant prep that often accompanies a colonoscopy.
"No one wants to be part of that eight percent with a false negative," Dr. Rafferty says, "but if all you're willing to do is Cologuard, do Cologuard. I'm a firm believer that doing something is better than doing nothing."
Colonoscopy – the Gold Standard
A colonoscopy is still the only test that both detects and prevents colon cancer. During a colonoscopy, a gastroenterologist inserts a colonoscope, a flexible tube with a small camera, and guides it to the end of your colon. Colonoscopies are 98 percent accurate at detecting cancer, but the benefits go beyond detection. Many polyps found during the procedure can be immediately removed and sent for biopsy.
"It's still the most accurate way to find and diagnose what you have going on," Dr. Rafferty says. "Plus, if the doctor can remove a polyp, which is often the case, then just like that, the risk of cancer from that mass is gone."
Dr. Rafferty says the average precancerous polyp takes about ten years to develop into cancer, though every case is different. That's why experts recommend a colonoscopy every ten years after the first for those at average risk.
The recommendation is every five years for those at higher risk such as those with a personal or family history of polyps or cancer, pre-existing GI problems such as IBS, genetic markers for colorectal cancer, or those who have had previous polyps.
Of course, these recommendations are for screening, not for diagnosis, Dr. Rafferty points out.
"Once you have symptoms, you move from screening exam to diagnostic exam" she says. "It's important to pay attention to your own body and not rely only on the screening schedule. If you have had episodes of bleeding, it needs to be evaluated- even if your next surveillance colonoscopy is not yet due. Discovering cancer early is the key to survivorship".
The Colonoscopy Stigma
There are many reasons why some prefer screening at home or no screening at all. When it comes to preventative medicine associated with aging, colonoscopies are the "butt" of many jokes.
"I get it," Dr. Rafferty says. "They don't want somebody looking at their bottom. Well, they're not looking at your bottom. They're looking at your colon- and every one of us has one. If you're worried about the embarrassment or the endoscopy experience, please don't. They roll you over, and the next thing you know, you wake up and it's over."
Dr. Rafferty also acknowledges the reluctance due to the poor taste of the prep, and fasting required to clean out your digestive system prior to the test.
"It's not fun, but think of a how it feels to have a bad case of diarrhea, by accidentally drinking something that makes your stomach churn," she says. "At worst, that's what you experience. And that's nowhere near as bad as what you could experience with progressive cancer. Plus, there are alternatives for those who can't use traditional prep- such as those at risk of serious side effects of dehydration, or who can't handle the salt load due to kidney problems. If you have concerns about the prep, that's a conversation for you to have with your doctor."
Talk to your primary care provider to schedule a colonoscopy or to discuss what screening is best for you.