One of the main themes in medicine over the past year or two has been the value (or lack of same) of screening as a tool to prevent early death.
Accepted medical practices have been challenged, as data become available that are not only counterintuitive, but in some cases almost heresy.
Examples include:
Is routine mammography harmful or helpful?
Should the prostate specific antigen (PSA) test be used at all?
Do annual exams save lives?
We have written about these issues frequently- mammography, the PSA test, annual physicals. The above links give a good summary of our take on each of these issues.
Another important example is the evolution of data-based questioning of medical dogma, mostly the recommendations of the interval between tests, and the age of those being tested. Colonoscopy certainly does save lives, but how it is used is still an open question.
Thanks to improved imaging techniques, virtual colonoscopy previously considered to be inferior to optical (standard) procedure may be evolving as a suitable alternative. And possibly even a superior one.
The knock on virtual colonoscopy is that if polyps possible precursors to colorectal cancer are found, then the patient must then undergo the standard procedure to remove the polyps. There have also been discussions about which method is better at detecting polyps.
And of course, most people know that the colonoscopy itself is a non-event (you are asleep). It is the preparation to cleanse the bowels the day before that is unpleasant. Which may be an understatement.
So, is it possible to derive the benefits of colon cancer screening without having to suffer the indignities of the cleansing? And if so, is the virtual colonoscopy sufficient in detecting polyps?
Surprisingly, the virtual procedure, which is less unpleasant to prepare for, may actually be superior to the optical method.
These issues are clearly discussed in Ann Brenoff s recent article on the HuffPo site entitled 5 Reasons Why Virtual Colonoscopies Are Better ... And Why Your Doctor May Not Do Them.
Although Brenoff focuses on the economic incentives for physicians to use the optical method, she also provides valuable information about the differences between the two procedures.
For example, the virtual procedure, according to Drs. Joel Bortz and Joseph Lebovic of LSG Imaging in California, the [scan] has led to the detection of many issues outside the intestines: pancreatic cancers, kidney stones, cysts in the liver, gallstones, lung cancer, and kidney obstructions -- all in patients with no symptoms.
Although this may seem to be an obvious benefit, this is also not clear. ACSH s Dr. Gil Ross says, Picking up multiple abnormalities detectable on various radiological studies done for unrelated issues does not necessarily mean that you ve done the patient a service. Far and away, most such serendipitous discoveries are found to be incidentalomas a semi-facetious term for things that are not supposed to be there but would do no harm and should be left alone. Unfortunately, the current climate of defensive medicine often means that more and more studies and procedures will be done to cure such innocuous abnormalities.
Brenoff also argues that the absence of general anaesthesia is a major advantage, but ACSH s Dr. Josh Bloom doesn t buy it. He says, Endoscopies and colonoscopies are done using a miracle drug called propofol. It is administered by IV, you are asleep in 10 seconds, and wake up feeling like you ve had the best nap of your life. And propofol is eliminated so quickly from your body that thirty minutes after they wake up most patients are getting dressed to leave.
He offers a bit of advice:If you are having an endoscopic procedure done and the anaesthesiologist is using an older method, turn around and run in the other direction. And then when you get there, keep going.
But most important is the question of whether the virtual exam can detect polyps as well as the optical exam. Surprisingly, the answer is: it does it better.
Brenoff explains, The doctor can see more with a virtual colonoscopy.
In a traditional colonoscopy, what is being examined is your intestines. A 5'7" scope with a camera on it is manually inserted through your rectum and the doctor can see and take photos of what the scope passes as it is is slowly pulled out. It sees things in one direction only and there is no doubling back.
But what about the advantage of being able to remove polyps should the be detected? The CT scan cannot do this.
Dr. Lebovic explains, For [polyps] greater than 1 cm, they [should be removed] -- but the chance of this occurring is just 6 percent... "So for 94 percent of the patients having this procedure done, this isn't a factor.
For the other six percent, he says, "We walk over to the phone and arrange to have the patient followed up with an optical exam.
Dr. Ross concludes, If this method encourages people who otherwise would have been afraid to have the test, it is indeed a huge advantage, and would no doubt save many who would have otherwise avoided such testing altogether.
