What have been common critiques of the study? What do its findings add to the literature?
Dr. Schnoll-Sussman: A common critique is that only 42% of the people that were invited to get a colonoscopy actually had the colonoscopy done. What this study proved is that if you do not have a colonoscopy, it is not going to work, and if you invite someone to get a colonoscopy and they do not have it done, it will not work.
But when you looked at the people who had the colonoscopy done, this was actually a success story. When they did the protocol analysis to look at those people who had the colonoscopy, there was a decrease in colon cancer in that patient population. And out of the ones that were done, they were extraordinarily safe. There were no perforations in this study, and there was also a low incidence of significant bleeding. Another thing that the findings add to the literature is the safety of colonoscopy screening itself.
Dr. Lebwohl: Among people who were invited to undergo colonoscopy, there was a small decrease in the risk of colon cancer and no change in colon cancer death. I would say this was a relatively underwhelming result. But it is highly likely that the reason this is underwhelming is that most people who were invited to the colonoscopy said no. I would say that the most relevant audience for this paper is the departments of health in European nations. They should take these results seriously and conclude that offering colonoscopy to their population is likely not to be widely accepted. Nearly 60% declined.
What do we already know about the effectiveness of colonoscopies? What still needs to be answered?
Dr. Schnoll-Sussman: The key thing is that there have been multiple studies that have shown that screening decreases the incidence of colon cancer and can improve mortality from colon cancer. And these are incredibly important things; we do not want misinterpretation of them. Screening saves lives. My message to the public is to get a colorectal cancer screening at the age of 45 and onward. And that there is patient preference for screening modalities; colonoscopies are not the only screening modality. If you are not interested in having a colonoscopy, you can do stool-based testing, among other alternatives.
Dr. Lebwohl: There are some important questions that we do need to answer about colonoscopies, such as whether a colonoscopy is a much better test than annual stool-based testing, in terms of the ability to prevent more cancer and more cancer deaths. We do not know the answer to that question yet, but there are ongoing trials that will be published in the next few years that will help us. But that is a comparison of two different ways to screen, which is important to remember. Whether to screen is a settled matter. It is lifesaving.
Felice Schnoll-Sussman, M.D., is a gastroenterologist and the director of The Jay Monahan Center for Gastrointestinal Health, director of endoscopy at NewYork-Presbyterian/Weill Cornell Medical Center, and a professor of clinical medicine at Weill Cornell Medicine.
Benjamin Lebwohl, M.D., M.S., is a gastroenterologist at NewYork-Presbyterian/Columbia University Irving Medical Center and the director of Clinical Research at the Celiac Disease Center at Columbia University, where he collaborates with investigators in the U.S. and abroad in epidemiology, patterns of care, natural history, and therapeutics. Dr. Lebwohl is also the Louis and Gloria Flanzer Scholar at Columbia University Irving Medical Center.