Tag Archive for: prevention

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 Identifying New Biomarkers in Fecal Samples to Detect Colorectal Cancer

Biomarkers allow scientists to identify certain diseases from a simple biological sample like urine, breath, or even feces. Volatile organic compounds (VOCs) are the byproducts of metabolic processes associated with cancer, necrosis, or other metabolic changes. Scientists have now identified a new biomarker associated with both colorectal cancer (CRC) and adenoma (noncancerous tumor) that can be used for detection.

The cross-sectional study included 24 newly diagnosed CRC patients, 24 patients with adenomas, and 32 individuals who had a normal colonoscopy between July 2017 and July 2020. Individuals with normal colonoscopies and those with adenomas had fecal samples collected before and after their colonoscopy. Samples were requested from CRC patients 3-4 weeks after diagnosis and before treatment.

Of the 60 VOCs identified, only 3 showed different peaks between CRC and the control groups: p-cresol, 1H-indole, and 3(4H)-DBZ. There was a statistically significant difference between p-cresol peak values in each group with the greatest difference between CRC and the control group. This was also the same for 3(4H)-DBZ. However, 1H-indole did not have a significant difference between the study groups.

After adjusting for sex, age, and body-mass index (BMI), the researchers found that only CRC was associated with increased p-cresol and 3(4H)-DBZ, and p-cresol seemed to be the best possible predictor of CRC. A combination of p-cresol and 3(4H)-DBZ “is also optimistic as a combined biomarker” according to the study authors.

p-cresol was also abundant among patients with adenomas compared to healthy controls. This was also the case after adjusting for age, sex, and BMI.

Although more work needs to be done to determine what processes produce these VOCs, these associations can launch a new set of studies to confirm its use in a clinical setting. Other biomarkers have been identified that can  predict CRC occurrence and mortality. Overall, the ability to better detect CRC and precancerous adenomas play an important role in global prevention efforts. A better understanding of the biological processes involved in these diseases is crucial for those efforts to be successful.

 

Kaylinn Escobar is a Colorectal Cancer Prevention Intern with the Colon Cancer Foundation.

Photo credit: National Cancer Institute on Unsplash

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Setting it Straight: The Colonoscopy Controversy

A new study published in the New England Journal of Medicine has sparked controversy—this 10-year study involving nearly 85,000 participants in Europe highlighted that colonoscopies cut the risk of colorectal cancer (CRC) only by about a fifth, far below estimates from earlier scientific studies, and didn’t substantially reduce deaths, raising the possibility that the invasive procedure is not worth it. Doctors in the U.S. are now concerned that the study’s results could cause doubt about the effectiveness of a colonoscopy, which is a recommended CRC screening approach for those 45 and older, to be conducted once in ten years. Despite the confusion about the effectiveness of colonoscopies, national news articles and gastroenterologists in the U.S. have rebuked these conclusions. 

A major limitation that experts found with the study was that only 42% of the people who were invited to get a colonoscopy actually had one. However, researchers still reported the outcomes for the entire cohort, regardless of whether or not they underwent a colonoscopy. The study found that of those who were invited to have a colonoscopy—whether they got it or not—there was an 18% reduction in developing the disease and no statistically significant reduction in the likelihood of CRC death. Many don’t believe that this is representative of what happens in the U.S., where colonoscopy is more widely accepted as a standard screening protocol compared to European countries, and was a serious shortcoming of the study. In fact, when the individuals who did not get a colonoscopy were removed from the study, the risk of developing CRC among those who did get a colonoscopy reduced by an estimated 31% and the risk of death reduced by about 50%.

As Robin Mendelsohn, MD, co-director of the Center for Young Onset Colorectal and Gastrointestinal Cancers at the Memorial Sloan Kettering Cancer Center, argues “in order for a colonoscopy to be effective, you have to have it done”.

Andrew Albert, MD, a member of the Colon Cancer Foundation (CCF)’s Interdisciplinary Medical Advisory Council (IMAC), said, “While the NordICC trial demonstrates the need for challenging the status quo related to colonoscopy, this remains an effective screening tool, particularly for individuals at average risk who may be on the fence about going in for screening. Misinformation is dangerous, especially in healthcare. If we miss catching colorectal cancer at an early stage—which is what a colonoscopy is very good at—it can have a big impact on survival. We need to remember that CRC is preventable, and treatable when caught early.”

IMAC member Matthew A. Weissman, MD, MBA, FAAP, told CCF, “I hope that the findings of this study, which have been taken out of context by many, will not discourage folks from getting screened for colon cancer by colonoscopy or other appropriate methods, which is extremely important in early detection (and prevention) of this deadly disease.”

In an accompanying editorial in the same issue, experts point to the need for a longer follow-up time for the impact of screening colonoscopy to be realized. They also point out that the skill of the endoscopist conducting the procedure has a significant impact on the detection rate—29% of endoscopists in the trial had an adenoma detection rate below the recommended 25%. 

Consequent to this study, the American Society for Gastrointestinal Endoscopy (ASGE) issued a public statement that colonoscopy remains the best and most proven way to detect and prevent CRC incidence and death. The American Cancer Society also weighed in on the study, pointing to the high number of participants who didn’t undergo the procedure. Adam Lessne, MD, a gastroenterologist at Gastro Health in Florida told VeryWell Health that “when you take away the limitations, it’s proven again that colonoscopies do save lives and they do reduce the risk of death.” 

The bottom line is that a screening test of any kind—stool-based or colonoscopy—is better than none, and CRC is preventable with regular screening. For detailed information on various CRC screening methods and current screening guidelines, visit this page on the Colon Cancer Foundation’s website. 

 

Kitty Chiu is a Colorectal Cancer Prevention Intern with the Colon Cancer Foundation.

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