Colon polyp type may be key to cancer risk

May 15, 2018

(HealthDay)—The type of colon polyp that's spotted during a colonoscopy may help predict the likelihood of colon cancer, new research shows.

These polyps—also called adenomas—can be labeled advanced or non-advanced, explained researchers at the University of Pittsburgh School of Medicine.

Their study of almost 16,000 who underwent found that the long-term risk for was 2.5 times greater for those with advanced polyps, compared to people without such growths.

On the other hand, non-advanced polyps did not increase the likelihood of developing the disease. These patients had the same risk as those who didn't have polyps, the investigators found.

"That's a provocative finding," said study lead researcher Dr. Robert Schoen. "It would suggest that if you have a polyp that is non-advanced, which is the case in about one-third of people undergoing screening, you don't need to come back as frequently for colonoscopy because your risk of is the same as if you didn't have any polyps."

Schoen is a professor of medicine and epidemiology at the university. The study was funded by the U.S. National Institutes of Health.

Colonoscopies can spot early cancers and in many cases can even prevent the disease as doctors remove potentially harmful polyps.

"One can actually prevent people from getting cancer, which is far better than just detecting it early," Schoen said. "But polyps are commonly found, and patients can find themselves returning for frequent follow-up colonoscopy procedures."

To find out if the type of colon polyp influences a patient's prognosis, Schoen's group tracked 15-year outcomes for 15,900 people who underwent a colonoscopy as part of a major U.S. cancer screening trial.

When the study began, colonoscopies revealed that 18 percent of patients had an advanced polyp, 32 percent had a non-advanced polyp, and 50 percent did not have any pre-cancerous polyps.

The study, published May 15 in the Journal of the American Medical Association, found that those with advanced polyps had a higher risk for colon cancer for the duration of the study.

"After an advanced polyp has been removed, the whole colon remains at risk for cancer, and periodic colonoscopy is needed," Schoen said.

But people with non-advanced polyps had the same long-term risk for cancer as those without polyps.

Schoen noted that, in the United States, people with one or two non-advanced polyps are typically advised to return for a repeat screening in five to 10 years.

The new study questions whether that might be necessary.

"Bringing everyone back at five years is incurring a lot of testing that may not be preventing much cancer because only a small fraction of polyps will ever turn into cancer," Schoen said. "Millions of people are receiving follow-up colonoscopy exams for non-advanced polyps. We need to find out what is necessary. Potentially, this is an area where we could reduce testing and costs."

Dr. David Weinberg is chair of the department of medicine at Fox Chase Cancer Center in Philadelphia. Looking over the new findings, he stressed that most people will never develop advanced colon polyps.

Weinberg agreed that the new findings question the wisdom of routine 5-year follow-up colonoscopies for people with low-grade polyps versus advanced growths.

"Colonoscopy is a relatively finite resource, even in the United States," he said. "Given the higher risk over time in patients with advanced adenomatous polyps, particular efforts should be devoted to making sure that these patients are regularly followed to identify colon and remove them."

Explore further: Certain types of polyps may warrant keeping closer tabs on the colon

More information: The American Cancer Society has more about colon cancer.

Related Stories

Certain types of polyps may warrant keeping closer tabs on the colon

April 13, 2016
Being on the lookout for certain features of polyps may help physicians keep a closer eye on patients at risk for colorectal cancer.

New colon cancer finding could lead to earlier diagnosis—and better outcomes

March 28, 2018
For many years, physicians have puzzled over why people with "clean" colonoscopies went on to develop colon cancer. New findings from the Oklahoma Medical Research may help explain why, and the discovery could lead to ways ...

Polyp removal doesn't always signal raised colon cancer risk, study says

August 27, 2014
(HealthDay)—Doctors may be performing too many repeat colonoscopies on people who've had pre-cancerous polyps removed during an earlier colon cancer screening, a new Norwegian study suggests.

Serrated polyps plus conventional adenomas may mean higher risk for colorectal cancer

October 11, 2017
Most colorectal cancer develops from precursors known as polyps, the most common and well researched of which are conventional adenomas. Conventional adenomas often progress to colorectal cancer through an intermediate step ...

Marker polyps do not cause cancer

November 24, 2014
Although serrated polyps usually are associated with colorectal cancer, it turns out that such polyps are themselves not dangerous, according to a Norwegian study released this week in BMJ Gut.

Recommended for you

Pregnant? Eating broccoli sprouts may reduce child's chances of breast cancer later in life

August 16, 2018
Researchers at the University of Alabama at Birmingham have found that a plant-based diet is more effective in preventing breast cancer later in life for the child if the mother consumed broccoli while pregnant. The 2018 ...

Three scientists share $500,000 prize for work on cancer therapy

August 15, 2018
Tumors once considered untreatable have disappeared and people previously given months to live are surviving for decades thanks to new therapies emerging from the work of three scientists chosen to receive a $500,000 medical ...

PARP inhibitor improves progression-free survival in patients with advanced breast cancers

August 15, 2018
In a randomized, Phase III trial led by researchers at The University of Texas MD Anderson Cancer Center, the PARP inhibitor talazoparib extended progression-free survival (PFS) and improved quality-of-life measures over ...

New clues into how 'trash bag of the cell' traps and seals off waste

August 15, 2018
The mechanics behind how an important process within the cell traps material before recycling it has puzzled scientists for years. But Penn State researchers have gained new insight into how this process seals off waste, ...

RUNX proteins act as regulators in DNA repair, study finds

August 15, 2018
A study by researchers from the Cancer Science Institute of Singapore (CSI Singapore) at the National University of Singapore has revealed that RUNX proteins are integral to efficient DNA repair via the Fanconi Anemia (FA) ...

Chemicals found in vegetables prevent colon cancer in mice

August 14, 2018
Chemicals produced by vegetables such as kale, cabbage and broccoli could help to maintain a healthy gut and prevent colon cancer, a new study from the Francis Crick Institute shows.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.