Clear Evidence Statistics Bear Out the Importance of Colonoscopies

The symptoms of colon cancer can be pronounced — unexplained changes in bowel habits, rectal bleeding, anemia, unexplained weight loss, and abdominal pain are just a few of them.

“With a good screening program, we often find cancer at earlier stages, and people can be treated and cured,” said Dr. Bradford Gray, a general surgeon at Holyoke Medical Center. “But if you wait long enough for it to become symptomatic, the colon cancer is typically at a much later stage. Bleeding might occur, or, if the cancer gets big enough, it may physically block the colon, although that’s usually not a typical symptom unless it’s very advanced.”

Unfortunately, these symptoms don’t occur right away, even though cancer might be developing for years. “That’s one of the problems with colon cancer: you may have it but not know it because it doesn’t cause symptoms until a much later stage.”

That’s why colonoscopy — a procedure used to look inside the colon and rectum — is so important. Colonoscopy can detect inflamed tissue, ulcers, and abnormal growths. The procedure is used to look for early signs of colorectal cancer and can help doctors diagnose some of those aforementioned symptoms.

“Colonoscopy is a process that screens for colon cancer by checking for pre-cancerous polyps or lesions,” said Dr. David Kalman, a gastroenterologist and president of Springfield Medical Associates. “It’s typically recommended for average-risk adults starting at age 50, or for those with a family history of colon cancer typically starting after age 40.”

Other risk factors change those recommendations as well, Kalman added. “Recent data suggests that African-American patients should start at age 45, and there’s also new data to suggest that obesity or smoking increases one’s risk for colon polyps or cancer. Having a personal history of inflammatory bowel disease or colitis also increases one’s risk, as well as certain hereditary forms of uterine cancer.”

Colon cancer affects slightly more men than women, but both genders are encouraged to follow these screening recommendations, he noted.

If a colonoscopy uncovers an advanced cancerous lesion, Kalman said, the five-year mortality rate after removal is above 50{06cf2b9696b159f874511d23dbc893eb1ac83014175ed30550cfff22781411e5}, but if the cancer has metastasized into other areas, that rate falls to around 5{06cf2b9696b159f874511d23dbc893eb1ac83014175ed30550cfff22781411e5} or less.

Still, even when presented with these facts, doctors say, many people remain reluctant to have colonoscopies done. That may be changing — with life-saving results.

The Ins and Outs

Colonoscopy is a fairly routine procedure, said Kalman and Gray.

As the patient lies on his or her left side on an examination table, the doctor inserts a long, flexible, lighted tube called a colonoscope into the anus and guides it through the rectum and into the colon. The scope inflates the large intestine with carbon dioxide gas to provide a better view, and a small camera on the scope transmits a video image from inside the large intestine.

During a colonoscopy, the doctor can also remove growths, called polyps, using tiny tools passed through the scope, and may also take samples from abnormal-looking tissues, to be biopsied for signs of disease.

After a screening regimen has begun — again, around age 50 for normal-risk patients — “depending upon the findings at the time, if the first colonoscopy is completely normal and there are no other risk factors, we’ll repeat it every 10 years,” Gray said. “But if they find certain kinds of polyps — tubular adenomas — we increase the frequency to every three to five years.

“If someone is at higher risk, depending on the circumstances, we’ll start screening at an earlier age than 50,” he added. For example, if someone was diagnosed with colon cancer at age 45, his offspring would be recommended to begin screening 10 years earlier, at age 35 — reflecting the fact that colon cancer develops slowly over time from when the first pre-cancerous polyps develop. “The idea of doing a colonoscopy is finding polyps, and if those polyps are left in place, then over the long term, they can turn into cancer.”

But many patients still take some convincing to begin regular screenings for colon cancer. Yet, the procedure, which has changed very little over the years, is surprisingly simple, Gray said.

“First, the person has to undergo bowel prep; they take an agent — typically a liquid by mouth — that has a cathartic effect and cleans all the stool out of the colon,” he explained. The colonoscopy is then normally performed the following day, with some sort of sedation given intravenously.

“Typically, they’re very anxious about the procedure, but what almost invariably happens is, they find they’re surprised when the procedure is done. The bowel prep tends to be the most unpleasant part of the experience, but the colonoscopy itself is really well-tolerated. Most people don’t remember having it done.”

Kalman agreed that the bowel prep is usually the biggest hurdle in the colonoscopy process. “But it’s a critically important part of the procedure, because it’s important for the physician to visualize the bowel well.”

Sometimes, he explained, patients become nauseous when taking the drink, or stop drinking it for another reason, or fail to change their diet in the way the doctor instructs. “People often have a big fear about bowel preparation — maybe somewhat excessive. So that’s probably the most challenging part of the procedure.”

As for the scoping itself, “there are some alternatives to what’s called traditional or endoscopic colonoscopy, including virtual colonoscopy, a CT-scan-based procedure,” he told HCN. “However, its sensitivity in detecting small polyps is limited, and for that reason it has not been approved by most third parties and Medicare.”

Screening to Live

There are a few challenges for the doctor in conducting colonoscopy. For instance, certain flat polyps or lesions can be difficult to detect, while lesions on the right side of the colon, which may behave differently, are also harder to visualize.

But overall, doctors say, the benefits of the procedure are obvious. Kalman cited a recent study, funded by the National Cancer Institute and other groups, and reported in the New England Journal of Medicine, that seems to put hard numbers to the life-saving potential of colonoscopy.

In the study, 2,602 patients who had adenomas removed were tracked over time — a median of 15.8 years — and just 12 had died from colorectal cancer. Given an estimated 25.4 expected deaths from colorectal cancer in the general population, the study suggested a 53{06cf2b9696b159f874511d23dbc893eb1ac83014175ed30550cfff22781411e5} reduction in mortality.

“We know most colon cancers arise from pre-cancerous polyps, and those polyps typically take several years to form into cancer,” he said. “Therefore, if you can intervene by removing the pre-cancerous lesions, as highlighted in the New England Journal of Medicine article, you can reduce colon-cancer mortality significantly.”

Kalman said those results can be magnified by education and awareness efforts targeting high-risk groups.

“We’re probably still missing target groups in underserved areas,” he told HCN. “African-American patients are considered at a higher risk, so we should probably be gearing toward those patients, as well as patients with diabetes and smokers. But as a whole, in certain communities, like New York City and other metro areas, studies where we increased the screening of populations with programs run through health care centers, we decreased colon-cancer mortality rates.”

And those extra years and even decades of life, doctors say, are certainly worth a little inconvenience and anxiety.