I am trying to be well behaved, but I have to say that increasingly I am having a more difficult time controlling myself. My darling, loving wife, Wendy, says that I have to be nice and always listen to what others are saying. In theory that is great, but shouldn’t others also have to listen to what I have to say?

Today’s New York Times had a startling article that calls into question one of the bastions of belief about cancer detection. The article headline says it all.

Colonoscopies Miss Many Cancers

The article written by Gina Kolata says that that old reliable standby, colonoscopies, are not as accurate as we have been led to believe. It has been touted that if you have a colonoscopy and if any precancerous polyps are removed you should almost never get colon cancer.

Now we are told that colonoscopies can miss a type of polyp, described as a flat lesion or an indented one that nestles against the colon wall. A Canadian study, published in the journal Annals of Internal Medicine, found the test, while still widely recommended, was much less accurate than anyone expected.

As a matter of fact this study said that a colonoscopy missed just about every cancer in the right side of the colon, where about 40 percent of all cancers arise. Additionally, it also missed roughly a third of cancers in the left side of the colon.

Now, instead of preventing 90 percent of all colon cancers, as we have been told patients, colonoscopies might actually prevent only 60 percent to 70 percent of them!

According to Dr. David F. Ransohoff, a gastroenterologist, at the University of North Carolina, “This is a really dramatic result. It makes you step back and worry. What do we really know? ”

Despite these terrible numbers screening experts still are firm and say patients should continue to have the test, because it is still highly effective. The American Cancer Society has also said they have no plans to change their recommended intervals between screenings — the test still prevents most cancers, but the expense and risk of the test argue against doing it more often.

Colonoscopies are very expensive and very invasive. Additionally, the test carries a risk of perforating the bowel.

Some physicians have suggested that along with colonoscopies that patients have a stool test, the fecal occult blood test, between colonoscopies. It looks for blood in the stool, which can arise from colon cancer. However, the stool test can have false positives from things like red meat or broccoli that have nothing to do with colon cancer. Regular stool tests will lead to frequent false alarms and frequent colonoscopies without making much of a dent in the colon cancer death rate.

I remain a firm believer in regular colon screenings. It is clear, even with these abysmal numbers we will continue to use this invasive method to detect colon cancer, but we will also have our doctors continue to argue against PSA screens because they might lead to giving a biopsy to someone who does not have prostate cancer.

Go figure!

Joel T Nowak, MA, MSW