David Vining, MD

Colon cancer is the second-leading cause of cancer-related deaths in the United States, despite a 90% cure rate if detected early. The traditional method for screening is a colonoscopy, an invasive procedure recommended for the middle-aged population. In the early 1990s, however, David Vining, MD, professor of diagnostic radiology and medical director of the Image Processing and Visualization Laboratory at The University of Texas MD Anderson Cancer Center—then a fellow at Johns Hopkins—developed computed tomography colonography (CTC), a less invasive method of colon cancer screening.

“We had a computer lab with some donated equipment from Silicon Graphics—the company that used to make computers for movies like Terminator 2 and Jurassic Park,” said Vining. “I was playing video games at home at the time and was thinking, ‘If I can fly through these computer simulations, I can fly through the CT data.’ I wrote some software to take the spiral CT data, process it, and then fly through the reconstructed three-dimensional models.”

The first CTC procedure that Vining performed in 1993 took 8 hours to fly from one end of the colon to the other. Now, that same procedure can be performed in real time. Despite these technological advancements, CTC has not been widely adopted or used in the United States because of opposition from the gastroenterologists and a perception that the procedure is still experimental.

“Although the technology is certainly advanced and widely available, the perception in the public’s mind is that it’s experimental,” said Vining. “A colonoscopy is the gold standard. The phrase I often hear from the GI docs is that if virtual finds something, you will have to have a colonoscopy, so why not just undergo the colonoscopy in the first place? In the mind of the public, they decide just to undergo a colonoscopy. However, about eight out of 10 people have a normal colon. If they undergo a colonoscopy—if we screen everyone with colonoscopy—the vast majority are undergoing it unnecessarily.”

Another factor contributing to the scarcity of CTC in the United States is a lack of coverage from the Centers for Medicare and Medicaid Services (CMS) and a poor rating from the US Preventative Services Task Force. A new bill, HR 4165: CT Colonography Screening for Colorectal Cancer Act of 2012, has been introduced in an effort to force CMS to cover the procedure.

Unfortunately, Vining believes that this and any subsequent bill will be rejected because of the US Preventative Services Task Force rating of CTC, an argument that has been used to reject similar bills in the past.

“Until we get the US Preventative Services Task Force to upgrade its rating, it doesn’t matter how many bills are submitted or proposed,” said Vining. “I think that’s going to be the crux of the matter. The Task Force is an arm of the Agency for Healthcare Research and Quality (AHRQ) to which they’ll always go back. For CMS, I think the biggest issue is the additional cost [of CTC] that keeps it at bay, but they certainly use the Task Force report as a lightning rod to say, ‘We can’t approve it until they upgrade the recommendation.’ The US Preventative Services Task Force meets again this August to review those recommendations.”

Vining believes that the review of CTC by the Task Force is do or die for the procedure, and far more important than the passage of HR 4165. However, regardless of the Task Force ruling in August, CTC is not completely dead; many private insurance companies already cover it. But for CTC to become more widely used in the United States, CMS coverage for screening is crucial.