Friday, January 30, 2015

Colon Cancer Screening

Screening for colon cancer creates some interesting challenges.  I've never spoken with anyone who looks forward to a colonoscopy.  But finding colon cancer early through appropriate screening makes it a very survivable cancer.

A recent article focuses on other tests that can be used for first time screening.  For some time there has been the fecal occult blood test and the fecal immunochemical test.  These are very inexpensive and can be performed in or distributed by primary care providers.  The FIT is able to detect approximately 80 percent of colon cancers. And if it is done on an annual basis (rather than just once every ten years) then there is a good chance that a colon cancer that is not very aggressive would be caught a second time through.

There is a new test which is more expensive but requires very little change in normal behavior from the patient.  And while the article does not describe the test's sensitivity (i.e., ability to detect cases) if the sensitivity is higher than 80 percent that could make the extra expense worthwhile.

But, does this mean that these cheaper and less invasive tests will assure that everyone is getting colon cancer screenings at appropriate times and will they help to save money?  

Unfortunately, the answer may be no.

First, tests that are designed to be repeated annually rather than once every ten years could end up costing more if people actually use them annually.  It really depends on the relative price of the two tests.

Second, while sensitivity is important because we don't want to miss cancer cases, specificity is also important.  Specificity is making sure that we correctly identify the people who don't have cancer.  If we incorrectly suspect that someone has cancer we may put them through additional costly follow-up procedures that may create risks.  

Third, even the article referenced above states that based on a combination of family history and other risk factors, the less invasive tests are not necessarily optimal for everyone's first test.

So, while individuals may find less invasive tests more palatable and increase the screening rate and the lower cost per test is a good thing, without a modeling exercise to explore the various facets of how many are detected, how often people are screened, and how much money is saved as a result of earlier treatment, new best practice recommendations cannot yet be made.  

And if and when policy is changed will the consumers, the physicians (and which among them) or the insurers be winners?  

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