Some previous medical studies have found no significant difference in the diagnostic accuracy of CT colonography, also known as "virtual colonoscopy," and traditional optical colonoscopy. This study looks at whether both exams are as effective for adults over 65 as they are for adults between 50 and 65 years of age.
In the study, C. Daniel Johnson, M.D., professor and chair of radiology at Mayo Clinic in Scottsdale, Ariz., and a team of researchers conducted a follow-up analysis of data from the National CT Colonography Trial, in which 2,600 patients over the age of 50 underwent both virtual and optical colonoscopies at 15 centers around the country.
Dr. Johnson's team analyzed trial data from 477 patients over the age of 65 and 2,054 patients between the ages of 50 and 65 who were screened with the two procedures for clinically significant pre-cancerous growths called polyps. Patients in the study were comprised of both men and women at predominantly an average risk for colorectal cancer.
Cancerous lesions 1 centimeter or larger were found in 6.9 percent of patients in the 65 and older group and in 3.7 percent of the younger patients.
There was no significant difference in the accuracy of CT colonography for the detection of large and intermediate-sized cancers in the older participants compared to the younger participants. Sensitivity and specificity among the older and younger groups were 0.82 and 0.83 and 0.92 and 0.86, respectively.
"We found no statistical difference in the diagnostic performance between the two patient groups," Dr. Johnson said. "This is good information for patients of any age, as they can consider CT colonography as a valid option for colorectal cancer screening."
Colorectal cancer is the third most commonly diagnosed cancer in both men and women and the third leading cause of cancer deaths in the U.S. According to the American Cancer Society (ACS), a decline in colorectal cancer incidence rates over the last two decades is largely attributable to screening tests that allow polyps to be removed before they progress to cancer.
"I don't believe there is any screening test that can intervene as early in the biology of the tumor as colorectal cancer screening," Dr. Johnson said. "We have the opportunity to detect pre-malignant polyps, remove them and prevent an entire class of cancers."
Despite the effectiveness of colorectal cancer screening, the ACS estimates that only half of the U.S. population over the age 50 is being screened as recommended for the disease. Experts point to cost and a lack of access to health care as contributing factors.
Although both optical and virtual colonoscopy procedures typically require the use of laxatives to empty the colon prior to the test, there are major differences between the two exams.
In the traditional colonoscopy, an optical instrument called a colonoscope allows a physician to visually examine the colon and to remove polyps by passing a wire loop through the scope. In this procedure, the risk of perforating the bowel is higher and sedation is required.
"For the older patient, the risks of and recovery from sedation are issues," Dr. Johnson said.
Introduced in the 1990s, CT colonography produces cross-sectional, three-dimensional images of the entire colon and rectum. While the CTC exam itself is quicker to perform and about half the cost of the optical colonoscopy, it involves exposure to low doses of radiation and it must be repeated more often. When polyps 6 millimeters or larger are detected by CT colonography, the patient must undergo an optical colonoscopy to have them removed. In addition, incidental CT findings outside the colon might require additional follow-up.
"There isn't a fight between CT colonography and colonoscopy, but there is a fight in medicine against colon cancer," Dr. Johnson said. "We want patients to be screened. CT colonography is a preferred test for some patients and should be an option. Patients should talk to their doctor and choose the best option for them."
"The National CT Colonography Trial: Assessment of Accuracy in Participants Aged 65 and Older." Collaborating with Dr. Johnson were Benjamin A. Herman, S.M., Mei-Hsiu Chen, Ph.D., Alicia Y. Toledano, Sc.D., Jay P. Heiken, M.D., Abraham H. Dachman, M.D., Mark D. Kuo, M.D., Christine O. Menias, M.D., Bettina Siewert, M.D., Jugesh I. Cheema, M.D., Richard G. Obregon, M.D., Jeff L. Fidler, M.D., Peter Zimmerman, M.D., Karen M. Horton, M.D., Kevin J. Coakley, M.D., Revathy B. Iyer, M.D., Amy K. Hara, M.D., Robert A. Halvorsen Jr, M.D., Giovanna Casola, M.D., Judy Yee, M.D., Meredith Blevins, S.M., Lawrence J. Burgart, M.D., Paul J. Limburg, M.D., M.P.H., and Constantine A. Gatsonis, Ph.D.
Radiology is edited by Herbert Y. Kressel, M.D., Harvard Medical School, Boston, Mass., and owned and published by the Radiological Society of North America, Inc. (http://radiology.rsna.org/)
RSNA is an association of more than 48,000 radiologists, radiation oncologists, medical physicists and related scientists committed to excellence in patient care through education and research. The Society is based in Oak Brook, Ill. (http://www.RSNA.org)
For patient-friendly information on CT colonography, visit http://www.RadiologyInfo.org
Study tracks inner workings of the brain with new biosensor
16.08.2018 | Rheinische Friedrich-Wilhelms-Universität Bonn
Foods of the future
15.08.2018 | Georg-August-Universität Göttingen
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur
What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...
08.08.2018 | Event News
27.07.2018 | Event News
25.07.2018 | Event News
16.08.2018 | Life Sciences
16.08.2018 | Earth Sciences
16.08.2018 | Life Sciences