You know a colonoscopy can miss colon cancer, right? So find out exactly why, and what questions to ask your doctor.

Though a colonoscopy has saved the lives of many people by detecting precancerous polyps, it can also miss actual colon cancer.

“Endoscopy is not perfect and that’s tough fact to deal with as a gastroenterologist,” says Whitney Jones, MD, a national expert and frequent speaker on early-age onset colon cancer prevention, and Founder, Colon Cancer Prevention Project.

For average-risk people, colonoscopies should begin at age 45 — according to the U.S. Preventive Services Task Force — and be done every 10 years after.

“The 10 year interval as we all know is a negotiated time frame, not a date set in stone from God,” says Dr. Jones. “It’s the best estimate.”

The truth is, a colonoscopy can provide “incomplete protection,” adds Dr. Jones, which “usually lies with three factors.”

Three reasons a colonoscopy can miss colon cancer

#1. “Operator characteristics: Not all docs who do endoscopy do the procedure equally well,” says Dr. Jones.

“Many are benchmarking and working on continuous improvement, i.e., tracking fecal intubation rates, withdrawal times, adenoma [cancer] detection rates, of using split dose preps which better clean and prepare the right [sided] colon.

“These are questions any person having a colonoscopy should ask their physician.”

The second reason a colonoscopy can miss colon cancer is “anatomic considerations,” says Dr. Jones.

“It is impossible to see every square cm of the colon with any modality. There is a miss rate of up to 10% for 1cm adenomas, even by experts.”

Reason #3 for why a colonoscopy can miss colon cancer: “Biological issues: Right colon adenomas are much more likely to have an evolving pathology called serrated adenomas; these polyps evolve into cancer through a different pathway called hyper- methylation. They are not your mother’s colon polyps/cancers.

“They have several differences including a more flat nature, making them harder to identify, be obscured with mucus or stool,  progress to cancer in a shorter time frame and be located obviously in the right colon, which is harder to reach.”

Dr. Jones advises high-risk people to request more frequent screening and to consider asking their doctor for a stool test between colonoscopies.

Ask for a fecal immunohistochemical testing KIT.

Dr. Jones’ practice interests include prevention and treatment of colon cancers, pancreatic disease and biliary disease. He has authored numerous scientific articles, reviews and abstracts and presented at a variety of national and international scientific meetings.
Lorra Garrick has been covering medical, fitness and cybersecurity topics for many years, having written thousands of articles for print magazines and websites, including as a ghostwriter. She’s also a former ACE-certified personal trainer.  




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