New Blood Test Detects Colon Cancer - Will Colonoscopy Survive?

Over the past several decades, I’ve earned a good portion of my living performing colonoscopies – tens of thousands of them.  And risking a charge of heresy, I’ll say out loud that patients deserve a better colon cancer screening experience.  Progress is just around the corner.  Here’s a list of negative aspects of the colonoscopy experience.  I’ve got some street cred here.  Although I am usually on the operator end of the scope, I’ve also personally experienced the light at the end of the tunnel.

• Pre-test anxiety over the outcome.
• Ingesting liquid dynamite – often in the middle of the night -  and praying for a complete cleanse.
• Time away from work.
• D-day!  Enjoy IV needle placement, repetitive interviews, posh medical garments and the dignity of a public airing of high-amplitude flatus.
• The procedure has risks of complications, albeit at a low rate of occurrence.
• Driver must be present.
• Post-test anxiety over pending biopsy results.
• High aggregate cost including fees from the physician, facility, pathologist and anesthesia, unless your insurance company has managed to bundle these together.

The prep is more fun than the procedure!

Most colonoscopy results are either completely normal or have small benign polyps.  The percentage of patients who are found to harbor a significant polyp or actual cancer is low.  (Some doctors will argue that removing even a very small pre-cancerous polyp benefits the individual but I think this point is arguable.) In other words, the wide colonoscopy screening net catches a lot of very low-risk individuals.

Is this really the best that we can do?

Anyone who has watched television recently is aware of Cologuard, a stool test prepared by the patient and analyzed for DNA fragments and microscopic blood which, if present, may indicate the presence of a large polyp or even a cancer.  The test provides less protection than colonoscopies, which is why Cologuard is recommended on a triennial cycle, more often than routine colonoscopy exams.  But one must admit that Cologuard is orders of magnitude more convenient than a colonoscopy. However, I’ll bet that when most doctors come of age, which has recently been lowered to 45 years old, they will choose colonoscopy to protect themselves. 

Very recently, a new blood test was announced that detected nearly 90% of colon cancers.  While this sounds like a game-changer, I say not so fast.  What this means is that if you have colon cancer, there’s a 90% chance that this test will detect it.  But the vast majority of folks, those who are now getting colonoscopies to search for pre-cancerous polyps, do not have cancer.  So this new test doesn’t apply to them.  So the target audience for this new test is very small.

The holy grail for colon cancer prevention is a test that accurately, safely, and inexpensively determines one’s risk for developing the disease.  Experts can determine the proper medical response to various risk levels.  Colonoscopy has largely been a one-size-fits-all all strategy that deserves to be replaced and it will be.