Endoscopy Center

Frequently Asked Questions About Colonoscopy Screening

Colon cancer is already the third-leading cause of cancer death in the United States. More than 50,000 are estimated to die of colon cancer in 2022, but for most, it is largely preventable. The rise of routine colon screening for adults over 50 has brought cancer rates down significantly over the past 20 years, but rates among adults 45-50 have begun to rise.

For that reason, the U.S. Preventive Services Task Force (USPSTF) recently lowered the recommended age to begin routine colon screens from 50 to 45. 

Dr. Tilson explains the benefits of colon screening, and the risks of waiting too long.

The word screening often gets misinterpreted. We are not screening for colon cancer, we are screening for colon polyps that are precancerous. A Colonoscopy is a prevention test, and there are not many prevention tests in medicine. The only other cancers that we can significantly prevent medically are cervical cancer by getting the HPV vaccine, and liver cancer by getting the Hepatitis B vaccine. That’s it.

You develop cancer in your colon from very small growths called polyps. Once those polyps develop, they can eventually turn into colon cancer. We’re not very good at deciphering which polyps will turn into cancer, so during a colonoscopy we remove all of them.

About 8 years ago, the American Council of Gastroenterologists said people of African American descent should begin colon screening at 45, because evidence showed the rate of colon cancers started earlier in that population. Then in the last few years, they found that rates of colon cancers in the white population paralleled that of the African American population and they shifted the recommendation for everyone.

Learn more about the U.S. Preventive Services Task Force (USPSTF) recommendation. 

It used to be in three different ways. There was a procedure called a flexible sigmoidoscopy that went into the end of the bowel, but we’ve learned that if you only look in 1/3 of the bowel, you miss 2/3 of cancer. There is also the Cologuard-style test that looks for blood and abnormal DNA in your stool, and finds about 92 percent of existing colon cancers. But by far the most accurate screen is with a colonoscopy, which looks at the lining of the bowel for polyps and then removes them. This prevents at least 95% of colon cancers that can occur.

The stool test misses about 1 in 12 cancers and about 60 percent of polyps. And because Colonoscopy visualizes and prevents Colorectal (Colon) Cancer, if you don’t have a high-risk profile you don’t need to have another one for 10 years. If you get one at 45, you are all set for 10 years.

If you have a family history with either a lot of people who have had Colorectal (Colon) Cancer or family members who have had a lot of different cancers, you should talk to a doctor, who may recommend getting colonoscopies every few years. There are also those who deal with chronic inflammation like Crohn’s disease or ulcerative colitis. Because inflammation can lead to a higher rate of cancer, they also get colonoscopies at a higher interval. If a Colonoscopy discovers a lot of polyps, that may also lead to a higher prevalence of surveillance.

When you get a Colonoscopy, you limit your diet for a day or so and take a really strong laxative to clean out the colon, which allows us to take a tube, a light and a camera to look through the bowel. Because it would be uncomfortable if we didn’t give you anything, we give you medicine to make you feel relaxed and not feel the procedure at all. Many find the preparation to be more unpleasant than the colonoscopy itself.

Because we use sedation to get people relaxed, you do need to take a day out of your life and not drive or work on the day of the test. You feel like you can go back to work, but you don’t want to do any high level thinking.

I’ve diagnosed more cancer this year than I have than in any year that I’ve practiced.  We went almost a year where people delayed getting a test. A year makes a difference. To put things in perspective, it takes about 7-10 years for a small polyp to turn into cancer. But once it’s cancerous, it takes far less than that to where it may not surgically operable and it spreads.

Because this recommendation is put out by the U.S. Preventive Services Task Force (USPSTF), insurance is required to pay for every aspect of your colon cancer screening. In January of 2022, the federal government announced that insurance must also cover, without cost sharing, a follow-up Colonoscopy to evaluate a positive, non-invasive stool test like Cologuard, effective May 31, 2022.


James H. Reichheld, MD, is a board-certified gastroenterologist and Medical Director of The Endoscopy Center at Lowell General Hospital. Here he shares some important information about colonoscopy screenings and guidelines, and ways to reduce your risk for colon cancer.

Colonoscopy Screening FAQs

Colorectal Cancer usually begins with small growths, called colon polyps, inside the large intestine or rectum. Cancers in the colon or rectum develop very slowly, over a period of about 10 years. Cancer in these areas is very preventable. In fact, detection and removal of these precancerous polyps means that it is highly unlikely that an individual will develop colon cancer.

Anyone can get colon cancer, however, men have a higher incidence than women, and it is more common in adults 50 and over, or if there is a family history of the disease.

The most accurate way to detect colon cancer is by having a Colonoscopy, which is considered the gold standard of colon cancer screening due to its high sensitivity. The procedure is done with a colonoscope, which is a long flexible instrument that has a small video camera on the end so we can examine the lining of the colon. This high-definition camera helps us find very small polyps, even those as small as an eighth of an inch.

The great thing about a screening Colonoscopy is that the procedure is both diagnostic and therapeutic. If we find colon polyps, we are able to remove them at the same time, avoiding the need for an additional procedure. If we find something that looks more advanced or possibly cancerous, we are able to coordinate a consultation with a colorectal surgeon at Lowell General right away to determine if surgery may be needed.

The American Cancer Society recommends Colonoscopy screening at age 50. In 2021, the U.S. Preventive Services Task Force (USPSTF) lowered the recommended age to begin routine colon screens from 50 to 45

People at high risk, such as those with a family history of colon polyps or Colorectal (Colon) Cancer, should talk with their doctor about being screened at an earlier age. And of course, if you have any symptoms such as abdominal pain, blood in the stool or a change in bowel habits you should be seen by your physician right away. If nothing is found, the test typically does not need to be repeated for another 10 years.

Today, colonoscopies are performed with medications that should completely prevent discomfort. In fact, most patients find the preparation the most challenging part, as it involves drinking a solution that cleanses the colon so we can get a clear picture of the lining. My patients often tell me they wish they hadn’t worried so much about having it done, and done it sooner.

Having the recommended screenings, eating well with a diet high in fruit and vegetables, regular daily exercise of at least 30 minutes a day, and not smoking are the best things you can do to prevent Colorectal (Colon) Cancer.


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