Public Health Meets Policy: Colon Cancer Screening

March 11, 2009— -- It's fitting that during Colorectal Cancer Awareness Month there is an intense discussion in the medical and regulatory communities and elsewhere about whether we should offer Medicare patients the option of a new screening test for colorectal cancer.

The test is called CT colonography, or virtual colonoscopy. In short, it is a CT scan that can find polyps and cancers in the colon with X-rays.

As of now, the odds are against Medicare coverage for this test. But there is still time for the Centers for Medicare and Medicaid Services (which runs the Medicare program) to review comments from interested parties and perhaps reconsider its recent preliminary "noncoverage" decision.

Should Colon Screening Go Virtual?

I previously wrote about CTC in 2007 when an article was published in the New England Journal of Medicine that supported the use of this test as an alternative to traditional colonoscopy for colorectal cancer screening. Another article published more recently in September 2008 reported on the results from a carefully done trial in which CTC was compared with traditional colonoscopy as a screening test, and fared well.

In March of 2008, the American Cancer Society published new guidelines for the prevention and early detection of colorectal cancer. The society was joined by other professional organizations in writing the guidelines.

One of the key recommendations in the report was that we should favor tests that can prevent colorectal cancer, primarily through the detection of precancerous polyps which, when removed, do not go on to become cancers. It was in this vein that CT colonography was recommended as another option to find these pre-cancerous polyps as part of those guidelines.

But, despite this recommendation, concerns about CTC have persisted.

One key issue surrounding CTC is that if a suspicious polyp or lesion is found on the X-ray, then the patient still has to undergo a traditional colonoscopy to remove the polyp or biopsy the abnormal lesion.

Some centers can do this immediately "on demand." But many cannot, so it means the patient would have to undergo another bowel cleansing and colonoscopy on a different day. Going through a bowel prep for colonoscopy -- whether CTC or traditional -- is not anyone's idea of a fun time.

The good news is that with improving technology, CTC has become much more effective at finding polyps that are more commonly associated with a higher risk of becoming cancer. And that technology continues to improve.

Test Has Pros, Cons

Unlike traditional colonoscopy, a CTC does not require anesthetic and has a much lower risk of perforating the bowel, which can happen with the traditional study more often than most people realize.

On the other hand, CTC can be an uncomfortable test. It requires that air be forced into the colon while the patient lies on his or her stomach. Some people find that actually painful. There is also concern about the radiation dose associated with CTC.

Looming over all this is the fact that CTC is essentially a CT scan, and CT scans of the abdomen will find other things that may or may not be significant. That could lead to further diagnostic tests and surgery that might otherwise not have been needed for something that would never have caused a problem for the patient.

The American Cancer Society and its collaborators reviewed the evidence and thought that CTC should be an option for patients to consider "on the menu" for colorectal cancer screening, along with testing the stool for blood, routine colonoscopy, barium enema and sigmoidoscopy.

Others have reviewed the same evidence and come to different conclusions. They did not think the evidence is sufficient to support CTC as an alternative.

More recently, Medicare was asked to review the evidence on CTC and make a nationwide determination about whether it should be available for people on Medicare.

There is a very specific approach called a "national coverage decision" used by the Centers for Medicare and Medicaid Services to make these determinations. (Much of Medicare coverage is, in fact, based on "local" determinations by Medicare carriers, but that is beyond the scope of this discussion. In this case, the determination was going to be made by the central office in Baltimore.)

As part of that determination, they reviewed a significant amount of evidence, including a recent review and recommendation from the United States Preventive Services Task Force, that there was insufficient evidence to support CTC as an effective screening procedure for colorectal cancer.

The result is a preliminary conclusion from Centers for Medicare and Medicaid Services that the test will not be covered.

Is Colon Cancer Screening Worth the Investment?

Why is this so important, and why are so many organizations -- including the American Cancer Society -- working to have this decision reconsidered, or at least subject to further careful ongoing evaluation to answer some of the questions raised by the Centers for Medicare and Medicaid Services and the United States Preventive Services Task Force?

Colorectal cancer is the second leading cause of cancer death in this country. It affects both men and women, and overwhelmingly occurs in people age 65 and older. It increases in frequency the older we get.

Not Enough Screening for Colorectal Cancer

We know that colorectal cancer -- which takes the lives of almost 50,000 people a year in the United States -- could be prevented in many cases or at least found early if we followed the recommendations to screen for the disease.

Right now, some estimates are that about one-half of the people age 50 and older are getting screened. My personal hunch is that number is actually inflated. But even so, if only one in two people are taking advantage of screening for colorectal cancer, then we could do much better.

"Much better" in this case means that we could save thousands of lives every year when it comes to colorectal cancer if we only applied the knowledge we already have about screening for this disease. Even if we were perfect, we wouldn't find every case. But we would be a lot better off than we are now.

When you look at the age when colorectal cancer is diagnosed in the Medicare population, and realize that it takes 10 years or longer for many polyps to develop and become cancerous, then you wonder how many lives could be saved or at least relieved from the suffering that colorectal cancer brings, even if it occurs near the end of life.

It is my opinion and that of my colleagues here at the American Cancer Society that CTC could help reduce the disability and death from this disease. I suspect it will encourage more people to be screened for this cancer. Some of those people -- especially those in rural America -- may not have access to colonoscopy, given the shortage of trained colonoscopists in this country. CTC would probably assure 60 percent to 70 percent of the people screened with this new "virtual" test that they don't have a problem and don't need to go on to routine colonoscopy.

Treating colon cancer -- especially when it spreads -- is becoming more and more expensive, with the newer chemotherapy and targeted therapies that have become available. Reduce the incidence of colorectal cancer by finding a polyp in the colon before it becomes cancer and you not only reduce suffering but you reduce costs as well (by the way, estimates used to look at the cost effectiveness of CTC as part of this process applied data from 2003, which was well before the newer expensive drugs became available).

So, we find ourselves on the horns of a dilemma.

The American Cancer Society and others say CTC is an effective test and should be available from appropriately trained physicians and centers. Others look at the same data and conclude the test is not ready for prime time, calling for additional studies. Still others say we can do those studies while we are providing access to CTC with appropriate quality controls, yet there is no money to do the studies.

In Need of Medicare's Help

In the meantime, lives literally hang in the balance. And the people whose lives are hanging have no idea that they will be victims of colorectal cancer 5 years, 10 years or 15 years down the line.

We need to take a careful look at how we spend money for health care in this country. That is no secret and no surprise. But here we have an opportunity to do this the right way, while at the same time working together to answer the questions and be certain we do get it right.

Maybe CT colonography as a screening test is just the right place to start asking those questions and getting the answers, while saving lives as part of the process.

I don't think from a public health or public policy point of view it gets any better than that. But first, we need Medicare's help to get it done.

Len Lichtenfeld is deputy chief medical officer of the American Cancer Society. You can view the full blog by clicking here.