Researcher closing in on less invasive colon cancer test

Manasi Shah, Ph.D.

CANCER DIGEST – April 22, 2017 – If you’ve ever undergone a colonoscopy, you know why researchers are looking for a less invasive way to screen for colorectal cancer. 

Colonoscopy is currently the gold standard for detecting cancer, but it is a 2-day procedure that is expensive and dreaded by many. Patients need to drink a disagreeable laxative preparation to clean out the colon one day before the doctor threads a flexible colonscope through the intestines to look for and removing suspicious polyps. 

Analyzing fecal matter has long been sought as a less invasive means for detecting colorectal cancer, but until recently, the accuracy of the fecal occult test has not been as accurate as colonoscopy, but researchers are getting close to improving the accuracy by analyzing bacterial DNA.

In a new study in the journal Gut, researchers at The University of Texas Health Science Center at Houston (UTHealth) School of Public Health have identified specific strains of bacteria in the gut that are significantly associated with colorectal cancer. 

The researchers led by Manasi Shah, PhD, a graduate student at the University of Texas School of Public Health gathered data from nine of 12 published studies that analyzed associations between microbial bacteria and cancer.

A total of 509 samples (79 colorectal adenoma, 195 CRC and 235 controls) were analysed. After reanalyzing the large amounts of raw bacterial DNA sequence data from the studies using a variety of statistical tools, the scientists confirmed previously reported types of bacteria associated with colorectal cancer and identified other bacteria not previously associated with the disease.

What they found was that certain bacteria was significantly more prevalent in those with colorectal cancer than in those with no cancer. Using the bacteria as biomarkers for the disease, they were able to correctly identify the cancer patients 76.6 percent of the time.

“The fact that even when we combined several different studies we could correctly classify a sample as a colorectal cancer case or control with 80 percent accuracy solely based on microbial abundances was very encouraging,” Shah said.

Additional research will be needed to validate the tests. The goal is to develop a less invasive test for colorectal cancer to replace colonoscopy.

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