Colonoscopy is still the most recommended screening for colorectal cancer despite conflicting headlines and a flawed interpretation of a new study.

Effectiveness of colonoscopyA proven and widely used strategy for colorectal cancer screening and prevention.

The news headlines were interesting: “Disappointing results on colonoscopy benefits”; “New research suggests that the benefits of colonoscopy may be overestimated”; “In the gold-standard trial, invitation to colonoscopy reduced cancer incidence but not death“

While such news coverage has ignited debate and created some confusion about the study and its implications, the findings suggest that people question whether the usefulness and need for a colonoscopy are warranted.

as Cancer research scientist With over 20 years of experience in colorectal cancer screening and prevention, I am convinced that colonoscopy is one of the most important and effective tools for screening, detecting and preventing this common and deadly form of cancer.

Colorectal cancer is the fourth-most common cause of cancer death in the United States and the second-leading cause of death, according to the American Cancer Society. 151,000 new cases of colorectal cancer diagnosed in 2022 and nearly 53,000 deaths. Screening has contributed significantly a fall Colorectal cancer incidence and mortality over the past few decades.

the current US Preventive Services Task Force Guidelines People at average risk are recommended to start screening for colorectal cancer at age 45. This was recommended Reduced from 50 years of age in 2021 due to the recent increase in colorectal cancer incidence Prevalence in young adults.

Unpacking the new study

Several investigations have shown that screening colonoscopy Very effective In detecting and removing pre-cancerous polyps before they progress to cancer.

That’s why media coverage of new research published in the New England Journal of Medicine has caused confusion and concern among healthcare professionals and the public. Many of these news reports incorrectly interpreted the study as showing that colonoscopies had little effect on colorectal cancer incidence and were ineffective in reducing death. Such misinterpretations can have serious consequences for efforts aimed at screening and preventing a form of cancer that affects the health and well-being of many.

The story continues

In the study, a team of European researchers conducted a randomized clinical trial that examined the risk of colorectal cancer and death in healthy men and women aged 55 to 64. Study participants, who were recruited from population registries in Norway, Sweden, Poland and the Netherlands, were either invited or not invited to undergo a colonoscopy and received usual care.

After about 10 years, the research team collected data on colorectal cancer incidence and mortality among 28,220 people in the invited group and 56,365 in the invited group. They found that there was only an 18% reduction in the number of colorectal cancers in the invited group compared to those in the invited group. They also found that there was no significant reduction in mortality in the invited group. This seemingly disappointing result made many more confusing headlines in the media.

But there is a critical caveat to all this that explains. Only 42% of participants who were invited to undergo a colonoscopy did so. These percentages ranged from 33% in Poland, where most participants were recruited, to 60.7% in those from Norway.

When the researchers determined the benefits among those who actually underwent a colonoscopy, they found that colorectal cancer incidence decreased by 31% and death decreased by 50%—results that were much closer to theirs. Expected from other studies.

Another shortcoming of the study is the time between participant recruitment and screening. Colorectal cancer Usually slow to develop, it takes 10 or more years for a precancerous polyp to progress to cancer. Thus, the 10-year window used in the study may be too short to measure the full impact of colonoscopy screening. The authors acknowledge this and indicate that they will perform an analysis in 15 years.

These and other issues are clearly outlined in research responses from several medical and advocacy groups composed of experts with long-standing experience in colorectal cancer and its screening. This includes National Colorectal Cancer RoundtableThe Colorectal Cancer AllianceThe American Cancer Society And American Society for Gastrointestinal EndoscopyAmong others.

All responses emphasize that, despite the tone of much of the media coverage, nothing in the study changes the accepted reliability or effectiveness of colonoscopy screening. At best, the results confirm that for many, a simple invitation to screening does not necessarily promote participation in screening.

Colonoscopy remains the ‘gold standard’

During a colonoscopy, a long flexible tube is inserted into the rectum and moved through the colon to directly view, identify, image, and remove abnormal tissue such as precancerous polyps that may progress to colorectal cancer. As such, for quite some time, colonoscopies have been, and still are, considered the “gold standard” for colorectal cancer screening and prevention.

However, the method has several features that may deter people from opting for it. It is invasive, and has risks – albeit small – of Complexity. Additionally, for the procedure to be effective, the colon must be cleansed of any feces, a protocol that many find uncomfortable and uncomfortable. Finally, it can be expensive, creating barriers for those without adequate insurance coverage.

Although not as sensitive as colonoscopy, several are Non-invasive option For colorectal cancer screening that is currently available and recommended US Preventive Services Task Force For people with normal risk levels. Such options include stool tests High sensitivity guaiac fecal occult blood test, Stool immunochemical test And Multitarget stool DNA test.

The effectiveness of these methods varies and each has advantages and disadvantages. The preferred option is based on patient preference, determined by input from the medical provider. But those at higher risk, such as a family history of colorectal cancer, may have some symptoms, such as blood in the stool or a history of polyps Screening by a colonoscopy is recommended.

Importantly, non-invasive screening tests do not prevent disease by themselves. Rather, they raise the possibility that a benign polyp or tumor may be present, and therefore must be followed up with a colonoscopy to confirm and remove any abnormal lesions.

New directions for cancer screening

Recently, researchers have made significant progress in its development Liquid biopsy, which involves the profiling of informative biomarkers in fluids such as blood. This type of profiling identifies signals for the detection and monitoring of numerous cancers, including colorectal cancer.

There is particular enthusiasm in the scientific and medical communities around liquid biopsies that may help Early detection of multi-cancers. This method offers great potential for early detection of colorectal cancer as well as many other cancers for which there are currently no effective screening methods. Multi-cancer early detection tests are under development by many companies and are not yet approved by the Food and Drug Administration. There are several Currently available By prescription as a laboratory-developed test.

As with all non-invasive tests, liquid biopsies must be followed up properly to verify, remove and/or treat any identified lesions. Extensive research on liquid biopsy is underway, and the results indicate that a new generation of highly sensitive, accessible and patient-friendly cancer screening modes will emerge in the next few years.

Over the past few decades, screening has contributed significantly to a significant reduction in colorectal cancer incidence and mortality. Given the aging of the population, as well A recent increase in colorectal cancer In young adults, detecting the disease sensitively and in its early stages is more important than ever.

Reprinted from this article the conversation, an independent nonprofit news site dedicated to sharing ideas from academic experts It wrote: Franklin G. Berger, University of South Carolina. Conversations are different Interesting free newsletter.

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Franklin G. Berger receives funding from the Centers for Disease Control and Prevention