For the past few decades, optical colonoscopy has been the gold standard in colon cancer screening. However, recent studies have shown that virtual colonoscopy may be the safest and most cost-effective colon cancer screening method available. Cancer Care & Economics (CC&E) recently spoke with Abraham H. Dachman, MD, professor of radiology at the University of Chicago Hospitals. A nationally recognized expert in virtual colonoscopy, Dr. Dachman explained why this emerging technology deserves a prominent place in screening for colon cancer.
CC&E: Has virtual colonoscopy finally gained recognition as a cost-effective screening tool?
DR. DACHMAN: Yes. We've seen virtual colonoscopy evolve from basically being considered a research technology into an accepted, clinically viable procedure. The positive predictive value rates published to date, as well as results from ongoing screening programs, prove that virtual colonoscopy is a very sensitive and cost-effective screening tool when targeting individual polyps about 6.0 mm and greater. According to recent studies, targeting smaller lesions does little to reduce the incidence of colorectal cancer [CRC] and results in unnecessary costs. [See ONI, May 2007, page 54.]
CC&E: What improvements have we seen in virtual colonoscopy?
DR. DACHMAN: For one, advances in technology have made virtual colonoscopy a faster, more comfortable, and more automated exam. We now have dedicated rectal tubes and dedicated pressure-controlled carbon dioxide insufflators that are extremely safe. We also have faster CT scanners that essentially eliminate the imaging problems that arise with respiratory motion.
The computers and networks to reconstruct and send the images through programmable automation controller (PAC) systems to dedicated workstations are vastly improved. We have better software to interpret the cases using a host of techniques that include 2D and 3D, as well as novel views with interesting new reading tools for the radiologist.
The combination of these factors has resulted in the potential to learn how to read virtual colonoscopy in a time-
efficient manner, and although there is still a long learning curve, an experienced reader can interpret most cases in 10 to 15 minutes.
