Thursday, June 2, 2011

Why You Need a Colonoscopy

One of my pet peeves as a Physician is when people talk about screening tests "Preventing Cancer".  Mammograms, pap tests, prostate tests (PSA), X-rays, blood tests, ultrasounds do not prevent cancer.  The best they can do is detect an abnormality early and allow for treatment.  None of those tests prevent a malignancy.  There is one screening test, however, that CAN prevent cancer and that is a Colonoscopy.  This is because of the natural history of colon cancer.

Colon cancer starts with small benign growths called polyps that progress through several stages of cellular change and transform from normal tissue into adenocarcinoma.  This is usually a slow process that takes  years to occur.  Certain genetic factors are at play and not all polyps develop into cancer.  But identifying and removing polyps that are found at a screening colonoscopy prevents colon cancer.

Isn't that amazing?

If there is no family history of colon cancer, it is recommended that a screening colonoscopy begin at age 50.    If there are no polyps seen, the USMSTF guidelines recommend the next colonoscopy is 10 years later.

If a polyp is identified and removed, the follow-up colonoscopy depends upon the histologic type of polyp.  A small adenomatous polyp is re-screened in 5 years.  A  tubulovillous adenoma  should have a repeat procedure in 3 years. A hyperplastic polyp should be re-screened in 10 years because the risk of developing cancer is very low.  Despite these clear guidelines, many doctors recommend shorter intervals which results in significant expense and unnecessary discomfort and risk for the patient.

Colonoscopy is the only screening test I know of that can prevent cancer.  It is fairly simple, does not need to be done often and  if everyone over the age of 50 had screening,  it has been estimated that between 60-90% of deaths from colon cancer could be prevented (that’s potentially 30,000-45,000 lives saved) .  

If you are over 50 and have not had a colonoscopy...just do it!

(Hat tip to my blog buddy at Abnormal Facies for the great image and  information)


theYogadr said...

An article in the July 28, 2010 issue of the Journal of the American Medical Association concluded, “If de novo decisions were being made today about whether to initiate colonoscopy as a screening tool in place of sigmoidoscopy for average-risk individuals, in light of the available evidence doing so would probably be inappropriate.”

There's another side to the story. Here's a link to a down to earth explanation by another MD about why colonoscopy isn't such a great idea.

Toni Brayer, MD said...

Yogadr: I read Dr.Mcdougall's article and was not impressed by his arguments. He mixed up a lot of issues. First, there is no excuse for rude and domineering doctors(as he was angry that colonoscopy was recommended for his wife) but that is not the point here.
2nd, he talks about a 3 day bowel prep for colonoscopy. The prep is a liquid fast the day before with a laxative like product for bowel cleansing. Sigmoidoscopy requires the same fast and several enemas for cleansing.

As he points out, the colonoscopy visualizes the entire colon to the cecum compared to a limited view of the left colon with sigmoidoscopy.

He also compares his old fashioned rigid scope with colonoscopy. That is like taking about bleeding patients as a treatment for infection. Talk about the (not so) good old days!! Painful and ineffective. No one returned for a 2nd rigid scope!

He also mentions the risk of perforation which is exceedingly rare (1/1700) and usually in a diseased colon.

Finally, screening with sigmoidoscopy is a fine option if a person does not wish to have sedation or undergo full colonoscopy.

His recommendation on better diet is also valid but that is not a guarantee to protect against cancer. One must recognize that Dr. McDougall's views are his and his alone

Michael Kirsch, M.D. said...

Great stuff, Toni. I believe that screening colonoscopy is the right thing to do, but there is no double blinded controlled study supporting that it saves lives. Rigid sigmoidoscopy? What's that? An exhibit in a museum?

Dr Paula said...

Excellent post for reminding you readers to get a screening colonoscopy. I must disagree with you about PAP smears "not preventing malignancy." Women who have regular PAP tests can be diagnosed in the pre-cancerous stage (SIL or dysplasia) and monitored appropriately or treated before it progresses to cancer. PAP smears do save lives. I hope you will remind your readers of this. Respectfully posted.

Siri Nelson said...

I had my first screening colonoscopy about 2 weeks ago. It was MUCH easier than I imagined and definitely better than getting colon cancer! EVERYONE should be screened! Any woman out there that's had a baby or had a pap test has already had a "worse" procedure. Just DO IT!

Doctor on a bike said...

I tell a lot of my patients this same thing about this being the only screening test that prevents cancer. Nevertheless, some still balk. If I can't convince them, I take solace in the information Harriet Hall reviewed at Science Based Medicine

Anonymous said...

Thanks for the shout out Dr. Brayer :)

Flex sig is really not ideal because it gives an incomplete picture of the colon - if this were properly explained to patients, I'm not sure they would opt for it - why go through essentially the same procedure but leave a big question mark in the right colon?

Anonymous said...

For what it's worth, the standard screening for members of Kaiser Permanente (HMO in California and elsewhere) is a flexible sigmoidoscopy at age 50 and every 10 years thereafter. When I asked why a "flex sig" instead of full colonoscopy, I was told the less invasive procedure detects "80%" of the lesions a colonoscopy would, with less risk. The flex sig was no big deal (the prep was the only minor hassle), and I don't mind doing it again in 10 years.

Whether I'd been shortchanged is a matter of medical debate, but it's interesting if the recommendation varies depending on whether the practitioner is trying to contain costs (as at Kaiser), versus profiting from the more expensive procedure.

BrainDame said...

It is easy, it is quick, the risk is so low and the potential benefits enormous. Even as a "typical" physician who rarely finds time for my own health, had my first screening just a year after a turned 50. So glad I did.

dreambox hd said...

If a patient has a family history of cancer, he or she will need a colonoscopy more frequently. Colorectal cancer is the second leading cause of cancer deaths. Colonoscopy is an exam that allows a doctor to closely look at the inside of the entire colon.

transex milano said...

So, I do not really imagine this is likely to have success.

Anonymous said...

Great article. I'm a guy who avoids medical care, but when my doc told me to get a colonoscopy, I reluctantly did and it was life-saving. One serious issue: the drugs used (almost always midazolam (Versed) and fentanyl) are often implicated in serious. long-term memory long (Versed, not fentanyl). Check out for versed horror stories; fully 10% of patients are having horrible problems with this amnesia drug. Get you colonoscopy but list versed as an allergy (causes hives) don't want versed.

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