Colonoscopy Key to Preventing Colorectal Cancer


March is National Colorectal Cancer Awareness Month, and while this disease may not be a topic that people like to talk about, it’s imperative that this common cancer be discussed—even by people in their 30s and 40s.


Often thought of as an older person’s disease, colorectal cancer numbers are actually decreasing in that age group, while incidences of this cancer are increasing in the younger generation. A portion of this can be credited to screening—people over 50 are advised to have colonoscopies on a regular basis, while those of a younger age are not.


The reason it’s so important to have this screening is because if caught early enough, polyps can be removed before they become cancerous.


“Colon and rectal cancer almost always comes from polyps, which are benign when they first start growing,” explained Dr. Brad Levinson, a board-certified colon and rectal surgeon. “At this point, most people don’t have any signs or symptoms, so they don’t realize that the polyps are there.”


The fifth-most common cancer in the U.S., colorectal cancer is the third most lethal cancer behind breast and lung cancer. Approximately 150,000 cases of colon and rectal cancer are diagnosed in the U.S. each year, despite the fact that it can almost always be prevented.


Colonoscopies vs. Other Screening Tests

According to Dr. Levinson, the only way to safely and effectively detect colon and rectal cancer is through a colonoscopy, which uses a fiberoptic flexible scope to detect and remove benign and cancerous polyps. The patient is given intravenous medication which allows them to sleep during the 20- to 40-minute procedure, and if polyps are found, they are removed safely at that time.


“The main thing that people are concerned about is the oral prep that they need to take the day before the procedure,” said Dr. Levinson. “There is no need for patients to be drinking a gallon of fluid. We now have preps of much lower volumes that are relatively easy to drink.”

While there are other tests that can be used to discover colorectal cancer, Dr. Levinson said that they are far less accurate than a colonoscopy. Even if an issue is found, the person still needs to have a colonoscopy to remove polyps or to further investigate the problem.

“A lot of people have seen the test Cologuard® advertised, and while it can detect blood and abnormal cells in the stool, the problem is that it is not particularly accurate,” said Dr. Levinson. “It gives people a false sense of security.”


Studies on Cologuard® have shown a 12 percent false positive rate, which indicates a polyp or tumor, through there is actually no abnormality present. This means that a person may undergo a colonoscopy when it was not actually needed.


“The bigger issue is that the Cologuard® test has been shown to have a more than 40 percent false negative rate, which means that polyps or cancers aren’t being detected in a large percentage of patients,” said Dr. Levinson. “While it may be more convenient than a colonoscopy, it’s often inaccurate.”


Some people may choose to undergo a virtual colonoscopy, though this still requires an oral bowel preparation just like a true colonoscopy. “Since a virtual colonoscopy is a special kind of X-ray, the patient will be exposed to unnecessary radiation,” said Dr. Levinson. “In addition, a virtual colonoscopy misses many polyps, especially the smaller ones that could grow to become cancer.”


If a polyp is detected on a virtual colonoscopy, the person still needs to have an actual colonoscopy to remove it. “When it comes down to it, a true colonoscopy can’t be replaced by any other procedure,” said Dr. Levinson.


Who Needs a Colonoscopy?

Anyone 50 and over definitely should have a colonoscopy, even if they have no symptoms of the disease. If no polyps are detected, they can be retested every 5-10 years.


“If a person has had a colon or rectal cancer already treated, they will require follow-up colonoscopies on a regular basis,” said Dr. Levinson. “Anyone who has had a family member with polyps, especially first-degree relatives—such as a mother, father, sister or brother—will also require colonoscopies on a more frequent basis.”


Individuals who have diseases like inflammatory bowel disease (ulcerative colitis, Crohn’s disease) also need to get tested more frequently, as do those who have had radiation to the colon or rectum for other health issues.


People displaying symptoms should definitely be tested as well; these can include changes in bowel habits (diarrhea and/or constipation) over a period of days to weeks, rectal bleeding, diffuse or localized abdominal pain, or unexplained weight loss and loss of appetite.

One thing to note is that those who eat a high-fiber diet should still be screened, especially if they fit into any of these other categories.


“There is not one bit of evidence to show that colon or rectal cancers are caused by or affected by diet,” said Dr. Levinson, debunking the belief that high-fiber diets reduce these types of cancer. “I’m not saying that a high-fiber diet isn’t good for the GI system in general, but it does not lower the incidence of these cancers.”


While current recommendations focus on those over age 50, Dr. Levinson said that these age guidelines should not be considered absolutes.


“On the upper end, there is no specific age to stop having colonoscopies,” he said. “If a person ends up with a bowel blockage from cancer, they’ll need surgery. And a half-hour colonoscopy to prevent cancer is better than a two- to three-hour operation, possibly with subsequent chemotherapy, to treat cancer.”


People in their 30s and 40s should also talk to their doctors about getting colonoscopies, added Dr. Levinson, citing recent studies indicating that 12 percent of all colon and rectal cancers occur in adults below age 50.


“Every single day in the U.S., 49 new cases of these cancers are diagnosed in people below age 50,” he warned. “Approximately 18,000 Americans below age 50 were diagnosed with colon or rectal cancer last year.”


Studies have also shown that between 2007 to 2020, there was a 3.7 percent decrease in colon cancer in people over the age of 55, but an increase of 2 percent every year in people younger than 55.


“Most of these younger adults found to have colon cancer will die from it; usually within five years,” said Dr. Levison, adding that younger people may want to discuss having a colonoscopy with a colon and rectal specialist.


“We have progressed in colorectal cancer prevention, but we can do much better,” he added. “Hopefully, during National Colorectal Cancer Awareness Month, we will all put more thought into preventing this disease."

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