Studies Offer More Evidence That Colonoscopy Saves Lives
WEDNESDAY, Feb. 22 -- It's been found that removing precancerous polyps during colonoscopies can prevent deadly malignancies from developing. Now, new long-term research supports the idea that the screening test not only prevents colorectal cancers, but dramatically cuts deaths from the disease.
Analyzing the results of the National Polyp Study -- which followed about 2,600 patients whose precancerous polyps were taken out during colonoscopies for up to 23 years -- researchers from Memorial Sloan-Kettering Cancer Center in New York City and colleagues found that this course of action netted a 53 percent drop in colon and rectal cancer mortality compared to deaths expected among similar patients in the general population.
"This is very strong evidence that provides assurance that there is a long-term benefit to removing these polyps," said lead author Ann Zauber, a biostatistician at Sloan-Kettering. "Over more than 20 years, we're getting this very consistent decrease in colon cancer deaths, so that's very exciting."
The study is published Feb. 23 in the New England Journal of Medicine.
In a related study published in the same issue, researchers from Spain found that fecal immunochemical testing (FIT) -- which uses stool samples to detect the presence of colorectal cancer -- yielded similar detection rates as colonoscopy in finding cancerous lesions. However, colonoscopy detected more advanced polyps than FIT, though more people opted to participate in fecal testing.
Colorectal cancer, the third most common type of malignancy worldwide, is one of the few cancers that can be prevented when screening tests are done properly, experts said. But the invasive and involved nature of colonoscopy -- during which the bowel is viewed with a camera after a day-long bowel cleanse -- seems to deter about half of Americans who should be screened from undergoing the test. The U.S. Preventive Services Task Force recommends colorectal screening for those between 50 and 75.
"Research like this is still needed because despite all of what we know and recommend, the American people are still not good at getting screening. So we really have a ways to go," said Dr. David Bernstein, chief of the division of gastroenterology at North Shore University Hospital in Manhasset, N.Y. "To me, it's honestly a no-brainer."
The National Polyp Study, which involved seven clinical centers, also found that patients who had precancerous colon polyps removed had the same low death rate from colon cancer for up to 10 years after the procedure when compared to another group of patients in whom no such polyps were found. Researchers used the U.S. National Cancer Institute's Surveillance, Epidemiology and End Results population-based registry program to compare observed death rates in those with precancerous polyps to a similar group in the general population.
Meanwhile, the Spanish study, a trial involving more than 50,000 people that is still under way, will compare colorectal cancer deaths after either one-time colonoscopy screening or FIT screening every two years for a period of 10 years.
Dr. Anthony Starpoli, a gastroenterologist at Lenox Hill Hospital in New York City, said the Spanish study drives home the point that colonoscopy is superior to other types of screenings, but compliance with all types is low.
"It's easier to do FIT, but it's not a substitute for colonoscopy," he said. "It's a good screening test to do before colonoscopy, or in the interim between colonoscopies . . . but you would be surprised at how many people don't get FIT. It just does not get done."
Starpoli suggested that doctors spend more time explaining colonoscopy screening to patients instead of "simply mandating they have a test."
"I think this is the fault of the physicians," he said. "I think it's an education issue, and [these studies] help in the education. It's pretty clear-cut."
The U.S. Centers for Disease Control and Prevention has more on colorectal cancer screening.
Posted: February 2012