A new potential stool sample test could alert doctors to “hidden polyps” before they perform a colonoscopy.
Researchers say this fecal test could pick up a mutant gene found in flat polyps that are difficult to see during the procedure.
This early alert, the researchers say, could encourage medical professionals to search more closely during a colonoscopy.
They believe the test could help detect some colon cancers that are missed during initial colonoscopies.
“Some polyps are embedded in the surface of the colon, and they’re also flat and covered up,” David Jones, PhD, chair of cancer research at the Oklahoma Medical Research Foundation, said in a statement. “This makes them incredibly difficult for doctors to detect.”
Jones and his team published their findings today in the journal Plos One.
The announcement was tempered with some caution by others in the field.
Dr. Peter Stanich, a gastroenterologist at the Comprehensive Cancer Center at Ohio State University, says doctors like him who perform colonoscopies already assume every patient is high risk and search the colon extensively.
“If you see it, you see it. If you don’t see it, you don’t,” Stanich told Healthline. “This would not replace a good colonoscopy.”
However, Stanich says he welcomes any advancement that helps medical professionals get a quicker jump on colon cancer, which is easily treatable if detected early and difficult to treat in later stages.
“Anything we can do to pick up people at high risk is good,” he said.
What the research revealed
Jones and his team of researchers set out to discovery why people with “clean” colonoscopies went on to develop colon cancer.
They concluded that 30 to 40 percent of these colon cancer cases were caused by polyps that were hidden during colonoscopies.
So, the researchers examined the genetic composition of the flat, hidden polyps.
“Most cancers and most polyps need more than one mutation to form. However, in these polyps, only one gene, called BRAF, was mutated,” Jones said.
The team concluded a new stool sample test could be developed to identify this mutant gene in a person’s colon.
“If changes are present, it would be a way for the doctors to know to look for a hiding polyp,” he said.
In addition, further analysis by the researchers showed the mutation also caused a wave of alterations in a person’s DNA.
“It’s probably the change in BRAF combined with these changes that leads to polyps forming,” Jones explained.
Jones added that understanding the downstream effects of the BRAF mutation could allow for drug intervention to prevent this cascade of DNA changes from happening. Ultimately, this might prevent the colon cancer from developing.
Reaction to the research
Stanich said doctors in his field have been aware for a while of the BRAF mutation and the difficulty of spotting flat polyps that might contain the gene.
“They can be very subtle. They can be tricky to see,” he said.
He notes gastroenterologists now have better cameras and therefore a better chance of locating hidden polyps.
He also says there are stool sample tests now that look for indications of cancer-causing material in the colon.
“They’re one piece of the puzzle,” he said.
Stanich says he’d be interested to see what kind of test evolves from this research to determine if it would be a significant advancement.
It’s possible, he says, that a patient with a positive fecal test but a clean colonoscopy could be asked to return sooner for a follow-up colonoscopy.
The test could also encourage a reluctant patient with a positive fecal test to agree to a colonoscopy when they wouldn’t otherwise.
“There’s some merit in a stool test that helps colonoscopies,” said Stanich. “I’m just not sure this is the one.”
Dr. Len Lichtenfeld, the deputy chief medical officer for the American Cancer Society, said the study has an “aspirational goal.”
He said it would be an important advancement if it indeed provided doctors with more vital information.
“It might lead them to be more vigilant,” Lichtenfeld told Healthline. “It could very well serve as a signal.”
He notes that medical professionals are aware of the BRAF mutation in other cancers such as melanoma and lung cancer, but he's not certain whether this will eventually impact colonoscopies and colon cancer detection.
Still, he thinks the research is worth pursuing.
“There is a lot of interest in developing a variety of tests to detect colon cancer,” he said.