Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

’Virtual colonoscopy’ effective in finding most polyps but may miss small ones

21.04.2005


A type of noninvasive "virtual colonoscopy" can diagnose medium to large polyps as well as traditional colorectal probes can, but it may miss some smaller yet potentially cancerous growths, according to a new review of studies.



The review -- limited to comparing the traditional procedure to use of computer tomography as a method -- also finds that despite seeming advantage for the person being screened, there is no evidence that availability of the CT scan results in more screenings being done.

CT scanning uses computers and software to display images of the colon as if the viewer were seeing the inside of it through an endoscope, the instrument used in traditional colonoscopy. It does not require sedation, although it does require the same bowel-cleansing preparation as the older method.


The review is published by ECRI, a nonprofit health services research agency that produces systematic evidence reviews on medical devices, drugs, biotechnologies and procedures.

Because anything detected by a CT scan would necessitate a follow-up colonoscopy to confirm the finding and to remove the polyps, there is controversy over its value both to the individual and to the health care system.

Although the review included 23 studies of CT colonography, only one study, of 1,123 patients, directly compared colonoscopy and CT colonography in patients without any previous history of colorectal problems.

In that study, CT colonography detected 94 percent of polyps 10 millimeters and larger in diameter, while colonoscopy detected 88 percent of these polyps. CT colonography detected 89 percent of polyps six millimeters in diameter and larger, compared with 92 percent for colonoscopy.

"CT colonography can detect most large colorectal polyps and masses, but is less sensitive for detecting smaller polyps," the review concludes.

Other findings:

  • There is no direct evidence as to the effect of any method of screening on the prevention of colon cancer incidence or death.
  • Virtual colonoscopy is safer, although traditional colonoscopy has a very low rate of complications.
  • CT imaging reduces to almost nothing the chance that a colon exam cannot be completed, and it does find incidental conditions such as kidney stones and gall stones that would not be picked up by the older method.
  • Because the invasive colonoscopy is the standard by which all other screening methods are measured but is not perfect, there is a statistical chance that the findings underestimate the accuracy of the virtual colonoscopy.

Most colon polyps are not cancerous or become malignant so slowly that an individual will die of other causes before colorectal cancer develops, according to the report. But those larger than 10 millimeters are more likely to become malignant. Between six millimeters and 10 millimeters, there was no statistically significant difference between the methods in the studies reviewed.

"In some studies, patients who have undergone both conventional colonoscopy and CT colonography have expressed a preference for CT over the more invasive examination, but this does not necessarily mean they will accept one and not the other," according to the report.

Patients might find advantages to each type of test.

"CT is faster and noninvasive, but polyps can be diagnosed and removed during a single colonoscopy procedure, and patients may prefer being sedated for colonoscopy to being awake for CT," says Charles Turkelson, Ph.D., chief research analyst at ECRI.

"Since colonoscopy can achieve both the diagnosis and removal of polyps during one procedure, some patients may prefer it to colonography because they will only have to undergo the required bowel cleansing preparation once rather than twice, for the diagnostic CT colonography and then again for any necessary polyp removal," Turkelson says.

If CT colonography becomes more popular as a colorectal cancer screening test, the resulting increase in follow-up colonoscopies "could be quite substantial," according to the report.

"Patients must already wait months for an available appointment for routine colonoscopy, and in some areas of the United States, screening colonoscopy is unavailable at all because there are not sufficient personnel to perform the test," the ECRI authors write.

Guidelines published in 2003 by the American Gastroenterological Association and an evidence review by the Technology Assessment Center of the Blue Cross Blue Shield Associations of America in 2004 do not find enough evidence to recommend virtual colonoscopy.

CT colonography is not covered by Medicare or any of several private insurers surveyed in the ECRI report.

Colorectal cancer is the second most common cause of cancer-related death in the United States. About 145,000 cases of colorectal cancer will be diagnosed in the United States in 2005, according to the American Cancer Society. In 2000, according to the Centers for Disease Control and Prevention, only 42 percent of Americans age 50 or older had been screened, as recommended.

Laurie Menyo | EurekAlert!
Further information:
http://www.cfah.org
http://www.hbns.org
http://www.ecri.org

More articles from Health and Medicine:

nachricht Observing the cell's protein factories during self-assembly
15.06.2018 | Charité - Universitätsmedizin Berlin

nachricht Scientists unravel molecular mechanisms of Parkinson's disease
13.06.2018 | The Francis Crick Institute

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

Im Focus: Photoexcited graphene puzzle solved

A boost for graphene-based light detectors

Light detection and control lies at the heart of many modern device applications, such as smartphone cameras. Using graphene as a light-sensitive material for...

Im Focus: Water is not the same as water

Water molecules exist in two different forms with almost identical physical properties. For the first time, researchers have succeeded in separating the two forms to show that they can exhibit different chemical reactivities. These results were reported by researchers from the University of Basel and their colleagues in Hamburg in the scientific journal Nature Communications.

From a chemical perspective, water is a molecule in which a single oxygen atom is linked to two hydrogen atoms. It is less well known that water exists in two...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

A sprinkle of platinum nanoparticles onto graphene makes brain probes more sensitive

15.06.2018 | Materials Sciences

100 % Organic Farming in Bhutan – a Realistic Target?

15.06.2018 | Ecology, The Environment and Conservation

Perovskite-silicon solar cell research collaboration hits 25.2% efficiency

15.06.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>