Dec 06, 2015
The primary tools used to screen for colon cancer are sigmoidoscopes and colonoscopes. These devices are not disposable, so they must be sterilized between each use
About 80 percent of endoscopes are cleaned using Cidex (glutaraldehyde), which does NOT properly sterilize these tools, potentially allowing for the transfer of infectious material
Asking what solution is used to clean the scope is a key question that could save your life. Make sure it’s been sterilized with peracetic acid, to avoid potential transfer of infectious material from previous patientsBy Dr. Mercola
Colon cancer is the second leading cause of cancer-related deaths in the United States. According to the latest data1 from the Centers for Disease Control and Prevention (CDC), nearly 135,000 people were diagnosed with the disease in 2012, and more than 51,500 died from it that same year.
Men and women over the age of 50 at average risk of colorectal cancer are typically recommended to get tested either by flexible sigmoidoscopy every five years, or by colonoscopy every 10 years.2
But are these screening tests safe?
David Lewis, Ph.D., a retired microbiologist with the Environmental Protection Agency (EPA), is the whistleblower who exposed the still-ongoing fraud at the EPA with respect to biosolids. We discussed that topic in a previous interview.
Lewis is also the Director of Research for the Focus for Health Foundation.3
Here, we'll discuss another massive public health issue that he exposes in his book, "Science for Sale: How the US Government Uses Powerful Corporations and Leading Universities to Support Government Policies, Silence Top Scientists, Jeopardize Our Health, and Protect Corporate Profits."
In this interview, Lewis reveals shocking information about the tests routinely used to check for colon cancer, along with recommendations on how to avoid the contamination risks associated with them.
Non-Disposable Equipment Carries Contamination Risks
The primary tools used to test for colon cancer are flexible sigmoidoscopes and colonoscopes. Neither of these expensive pieces of equipment are disposable.
This means they must be thoroughly cleaned inside and out and sterilized before each use, and therein lies the problem, as the disinfection process used does not properly sterilize these tools.
Lewis worked at the EPA Office of Research and Development (ORD) for 31 years. His career was divided between environmental issues — where he became involved in the land application of sewage sludge or biosolids — and infection control issues.
"The topic we're discussing today came about on the heels of an outbreak of HIV in a dental practice in Florida in the late '80s or early '90s. Half a dozen patients contracted HIV that was matched to the dentist's HIV infection through DNA comparisons.
I became involved with that and discovered that the AIDS virus would become trapped in lubricants in dental drills and prophy angles used for cleaning and polishing teeth.
The HIV would be spit back out of those devices in the mouths of subsequent patients. HIV was still infectious even though [the dental devices] had been through normal CDC and Food and Drug Administration (FDA) recommended clean up procedures," he explains.
"Nobody really believed it until we published a study in Lancet and later in Nature Medicine demonstrating that you can actually see visible amounts of blood coming out of these dental devices when they're cleaned according to the industry standards."
As a result of that investigation, the FDA immediately changed its sterilization guidelines for dental equipment, and the CDC suggested Dr. Lewis investigate the contamination risk of flexible endoscopes, which was suspected to be an even bigger problem.
The Problem with Flexible Endoscopes
Indeed, the same lubricant problems observed in dental devices were found in flexible endoscopes, which are used for colorectal cancer screening and other procedures using flexible scopes, such as bronchoscopes for looking in the airways and lungs, and gastroscopes used to look into the stomach and the esophagus.
These devices have several basic components. One is a long, flexible tube with a tiny camera at the end, which allows the doctor to view the inside of your stomach or colon for example, to look for evidence of cancer or other conditions.
At the other end of that scope, there are a number of knobs that allow you to manipulate the scope while it’s in the patient. There are also two internal channels, and this is where most of the problems arise.
In flexible sigmoidoscopes, there's a biopsy channel and an air/water channel.
When the physician sees evidence of a tumor, he or she can insert a little claw through the endoscope, into the patient, and grab a piece of tissue and pull it back out through the biopsy channel.
The air/water channel allows the doctor to clean the lens of the camera, which frequently gets covered with blood and other patient material. This channel is much smaller than the biopsy channel, and this is where most of the contamination risk comes from.
There are sterile sheaths for esophagoscopes and bronchoscopes.4 These sterile sheaths contain sterile, disposable air-water and biopsy channels. However, sterile sheaths are NOT available for colon cancer screening devices.
"The biopsy channel in all flexible endoscopes is fully accessible to a brush so that when you're cleaning the device between patients, you can insert a long brush down that biopsy channel and brush it all clean ... It has to be completely cleaned out before it can be re-used on the next patient.
The big problem with these scopes is that the channel where the air and water flow through, which also gets contaminated with tissue, blood, feces, and all kinds of things, is not fully accessible in most flexible endoscopes. You can't get a brush all the way through it.
The most common problem the physician has is that when they insert the tube into the patient, the lens gets dirty and when they hit the button for the air/water channel, nothing happens.
The scope is so clogged up with patient material from previous patients that it's unusable. That's the problem we're talking about with the scopes today. Flexible endoscopes cannot be heat sterilized.
You can't cook [autoclave] these things between patients like you do in normal surgical devices."
So in a nutshell, doctors are re-using devices that are impossible to properly clean. It simply cannot be done. There is a solution: create flexible scopes that can be autoclaved (heat sterilized). But manufacturers have not been pressured to come up with such a design. As noted by Lewis, it really boils down to federal agencies failing to take the contamination issue seriously enough.
Scope Contamination Is a Very Real Risk
Lewis launched a study with a university in which he looked at the internal channels, the air/water channel, and the biopsy channel, and collected samples of patient material from those channels. He then tested various ways of treating that layer of patient material to determine what was required to remove it from the inner channels.
About 80 percent of the time, flexible endoscopes are simply submerged in a 2 percent glutaraldehyde solution for 10 to 15 minutes to disinfect them between patients. (Glutaraldehyde is like formaldehyde; it's just a smaller molecule.) The scope is then re-used. But Dr. Lewis demonstrated that you can submerge those devices for two hours and there's still infectious material, such as HIV, trapped inside those internal channels.
"We did publish a study in Nature Medicine in 1995, where we took the lubricants used in flexible endoscopes and exposed that to HIV-infected human blood, demonstrating that when you submerge flexible endoscopes in 2 percent glutaraldehyde, which is the most common disinfectant used for previous scopes between patients, the 2 [percent glutaraldehyde] was ineffective.
Not only does it not work, but it actually complicates the problem. What glutaraldehyde does is the same thing formaldehyde does. Formaldehyde is used for preserving [and embalming]. It doesn't dissolve the tissue, blood, and the bits of flesh that are trapped inside flexible endoscopes. It actually preserves them so they build up over time. You're exacerbating the cleaning problem when you use glutaraldehyde."
The other cleaning alternative, which is used on about 20 percent of flexible endoscopes in the U.S., is peracetic acid. Peracetic acid (which is similar to vinegar) is used in organic chemistry labs to dissolve proteins, and it does a FAR better job than glutaraldehyde. You can actually see the difference between the two with the naked eye.
In a flexible endoscope, if peracetic acid is used to clean it, the coating of the tube will be as white as it was the first time it was used. In scopes cleaned with glutaraldehyde solution, the channels have a dark, reddish brown coating — remnants of all the patients it's been used on.
"Say they want to take a biopsy; they run forceps through that biopsy channel. The sharp metal biopsy forceps scrapes that patient material off and it is being discharged down into the inside of the patient, in the colon, stomach, lungs, or wherever the biopsy is being taken. This gives you some visual idea of what's going on here," Lewis says.
With peracetic acid being so much better at cleaning the scopes where brushes can't reach, why are nearly 80 percent of clinics still using glutaraldehyde? According to Lewis, it's primarily a matter of economics. Even pennies per procedure add up when you're doing them by the thousands each year, and hospitals are under pressure to save money wherever they can.
"That's what's driving it. Below all of that is a simple problem that is sitting in the commissioner's office at the FDA. The FDA commissioner can write a letter and say, 'From henceforth, all air/water channels will be large enough in flexible endoscopes to get a brush all the way through them.' It's as simple as that.
Once the FDA does that, everybody who's working in the hospital with these devices is going to get a flexible endoscope that you can stick a brush through the air/water channel in. It doesn't get simpler than that," he notes.
When Getting a Colonoscopy, Make Sure Peracetic Acid Was Used to Clean the Scope
If you’re having a colonoscopy or any other procedure using a flexible endoscope done, be sure to ask how it was cleaned before your procedure, and which cleaning agent was used. If the hospital or clinic uses peracetic acid, your likelihood of contracting an infection from a previous patient is very slim. As noted by Lewis:
"[P]eracetic acid is a chemical sterilization procedure. It's not heat sterilization but still, visually, you can see the patient material thoroughly cleaned out ... In Athens, Georgia, I go and talk with the staff at the hospital where I have those procedures done and make sure they are using peracetic acid."
If the answer is glutaraldehyde, or the brand name Cidex (which is what 80 percent of clinics use), cancel your appointment and go elsewhere. Asking what they use to clean the scope is really a key question that could save your life.
It's so important that we all start to do this, because the FDA simply does not have the incentive to take action on it. But once enough people refuse to have these procedures done with glutaraldehyde-sterilized instruments, then clinics and hospitals will change, even if the FDA does nothing. It's also crucial that health care professionals who are reading this start addressing the issue from the inside. You really need to be aware of this issue, and how it's placing patients at risk.
"I sat down with the head of the FDA's devices group about 10 years ago. It's the last time I interacted with them on this face to face," Lewis says. "This was after Dr. Kessler left. I was simply trying to get the FDA to make hospitals follow the instructions on the bottle of Cidex (glutaraldehyde). Because it says, according to FDA guidelines, they've got to soak it for 45 minutes when most facilities only soak it for 10 minutes.
I said, 'Why are you letting everybody get away with this?' The head of the devices section looked at me and gave me two reasons. He said, 'There is a lack public concern on this issue.' Number two, 'There's not enough documented cases.' So, therein lies the way we've got to go, to move the FDA and the CDC on this issue.
We've got to inform the public and we must explain to the public that it is expensive to document these cases. It is almost never done. So it's not on the radar."
Should You Have Routine Colonoscopies to Check for Colon Cancer?
I'm 61 and I've never had a colonoscopy. It's not that I think they're ineffective as a diagnostic tool. I just feel really confident that with my diet and lifestyle I will probably never come down with colon cancer. Still, I may eventually have one, just as an insurance screening. That said, I do recommend colonoscopies. They're probably a good idea for most of us. Colon cancer grows very slowly, and it's one of the top leading cancers that kill people, so early detection is important.
Another common test for colon cancer is a guaiac stool detection test, which checks for hidden blood in your stool. This test has a lot of false positives. According to the latest evidence, this test doesn't work very well.
What does work well is visual inspection, which is what the colonoscopy allows your doctor to do. If polyps are found in their early stages, your doctor can simply snip them off right then and there. So a colonoscopy is not only a diagnostic tool, it can also serve as a surgical intervention. They take a picture of the polyp, clip it, capture it, and send it to biopsy. So it could save your life, and it's definitely something to consider.
However, you don't want to risk complications or infections by having the procedure done with a contaminated piece of equipment! So please, do make sure to ASK what they use to disinfect the scope, and agree to the procedure only in a facility that uses peracetic acid as a cleaning solution.
This is a very simple strategy that will not only protect your health, but as more people get wise to this and start demanding the use of peracetic acid, will improve the safety for all patients undergoing these procedures.