A recent European study that has garnered some mainstream press has controversially called into question the utility of undergoing a colonoscopy. Specifically, the study – conducted by the Nordic-European Initiative on Colorectal Cancer (NordICC) – followed participants who were invited to have a colonoscopy and compared them with participants who weren’t invited to undergo the procedure.
It concluded that the procedure only reduced the risk of developing colorectal cancer by 18% and did not significantly lower the risk of death from cancer. Several mainstream media outlets seized on the report to posit that colonoscopies may not be as effective as previously thought – or that they may not be necessary at all.
However, a closer look at the details of the NordICC study reveals why it shouldn’t be interpreted as a slam-dunk against having a screening test.
The study, which took place between 2009 and 2014, involved 84,585 participants from Poland, Norway, and Sweden – with just 42% actually undergoing a colonoscopy. The study also didn’t follow patients long enough to fully assess the risk of death from colorectal cancer. And some of the physicians who did the procedure didn’t meet a minimum quality benchmark.
Dr. David Leiberman, chair of the American Gastroenterological Association’s Colorectal Cancer Task Force, issued a statement noting that the NordICC study actually shows that among the patients who actually got the colonoscopy, there was a 31% increase in colorectal cancer prevention and a 50% decrease in mortality.
In addition, the quality of the NordICC colonoscopies are of concern. Screening standards in the U.S. set a 25% benchmark for adenoma detection rate (ADR), a numeric value that represents the percentage of times a gastroenterologist detects a precancerous polyp during screening colonoscopies.
“In this study, many endoscopists had ADRs below the 25% benchmark,” Dr. Leiberman said. “We know that low ADRs are associated with a higher risk of post-colonoscopy CRC (colorectal cancer). If you know your adenoma detection rate, compare it to the rates of the doctors in the study.”
Other points to keep in mind:
- Colorectal cancers can be slow to develop. Many patients in the study were followed for fewer than 10 years.
- The study age range was 55 to 64. The findings don’t address colorectal cancer detection and survival among younger or older patients.
- Colorectal cancer biology differs among ethnic groups. In the U.S., CRC death rates in Blacks are nearly 40% higher than those in non-Hispanic whites and 50% higher in American Indians and Alaska Natives (AIANs). The European countries in the study have significantly lower Black and AIAN populations.
The fact remains that, as is the case with so many diseases, early detection can be key to treatment and/or prevention. According to the American Cancer Society (ACS), excluding skin cancers, colorectal cancer is the third most common cancer diagnosed in the U.S. The ACS estimates that, in 2022 alone, the nation will record 106,180 new cases of colon cancer and 44,850 new cases of rectal cancer.
The U.S. Preventive Services Task Force (USPSTF) and the ACS continue to recommend that adults undergo colorectal cancer screening, including colonoscopy, beginning at age 45 and continuing until age 75. Adults aged 76 to 85 should consult their healthcare provider about a screening.
Furthermore, according to the Centers for Disease Control and Prevention (CDC), 68% of colorectal cancer deaths could be prevented with increased screening, with one of the most effective ways being a colonoscopy.
Clearly the idea that colonoscopies “might not be all that necessary” is inaccurate. I urge everyone to keep the above in mind before jumping to such conclusions.