Do You Really Need That Colonoscopy?

Another caveat is that the study’s follow-up period was roughly 10 years, says Ashwani Rajput, M.D., director of the Johns Hopkins Sidney Kimmel Cancer Center. And the benefits of screening are more obvious over time, he adds. The study’s authors plan to repeat their analysis at 15 years, so the results could change.

Finally, it should be noted that previous colonoscopy studies have shown a much greater risk reduction in both colorectal cancer incidence and death; so have studies evaluating other colorectal cancer screening methods.

“It should not be interpreted that colonoscopies aren't helpful. And most importantly, it should not be interpreted that there's not a benefit to colon cancer screening,” Meyerhardt says.

Bottom Line: Get screened and stay up to date on screenings

Despite headlines touting disappointing study results, experts say colonoscopies and colorectal cancer screenings, more generally, absolutely saves lives and shouldn’t be skipped. “There's no question that colorectal cancer screening works,” says Carole Macaron, M.D., a gastroenterologist at Cleveland Clinic, who points out that this latest study was really trying to assess the effectiveness of a colonoscopy as a public health intervention when it's being offered to a large group of people.

If you are at average risk for colon cancer — meaning you don’t have a family history of the disease or another condition that increases your chances of getting it, like Crohn's disease — routine screenings should start at age 45 and continue to 75. Whether you should continue screenings from age 76 to 84 is a decision you should make with your doctor. Adults 85 and older don’t need to be screened.

A colonoscopy is just one type of colorectal cancer screening. During this procedure, the doctor looks at the entire length of the colon using a flexible tool that has a camera attached at the end. One of the benefits to this screening is that if your doctor spots a polyp during the procedure (these are small clumps of cells that can be precancerous), they can take it out on the spot.

“If left inside 10, 15 years down the road [a polyp] could progress to cancer, so you want to remove them so that technically your risk of cancer from that polyp turns into zero,” Macaron says. If you opt for the colonoscopy, you should have it done every 10 years. If the test uncovers polyps your doctor might ask you to repeat the test sooner.

Other colorectal cancer screening options include a sigmoidoscopy, which is similar to a colonoscopy except the doctor only looks at a portion of the colon, and a CT colonography (or virtual colonoscopy), which takes images of the colon. Both of these options require more frequent screening than the colonoscopy; they should be done about every five years.

There are also screenings that you can do at home and send to a lab or your doctor’s office for analysis. These stool-based tests — which should be done every one to three years, depending on the type of test you choose — can detect blood or altered DNA in the stool, both of which raise red flags for cancer. It’s important to note that if your results from any of the alternative screenings come back abnormal, you will need to get a colonoscopy.

Not sure which screening to choose?

Talk to your doctor. There are pros and cons to each, and one might work better for your situation. “What matters is getting screened,” Macaron says. “That’s the endpoint.”

Still, millions of Americans aren’t getting tested. According to the Centers for Disease Control and Prevention (CDC) about 30 percent of adults ages 50 to 75 are not up to date on colorectal cancer screenings; roughly 20 percent have never been screened. And the pandemic has likely caused these percentages to grow, since the number of Americans getting screened for cancer in general has dropped dramatically as a result of COVID-19.

Meyerhardt’s advice: Don’t delay your colorectal cancer screening, whichever one you choose to get. “Catching people at later stages increases the likelihood that patients will not be cured of their cancer or will have a higher chance of their cancer coming back,” he says.

If caught early, the five-year survival rate for colorectal cancer is about 90 percent.