Yes, we know Dr. Oz's colonoscopy has gotten more than 35 bazillion hits on YouTube. He also had to do it twice. Because he didn't do the right prep, his physician, Dr. Jon LaPook, couldn't get a good look at some areas.

But not everyone gets such careful viewing of their intestinal tract. And that's the news: Turns out some docs doing colonoscopies are going too fast, or are not well-enough trained to find and remove all the benign polyps - called adenomas - that can develop into malignancies over time.
 

Best estimates are that around 32 percent of men and 15 percent to 20 percent of women will have these polyps. The doctor who performs your colonoscopy should have what is called an adenoma detection rate (ADR) of at least 20 percent, meaning that polyps are found in at least 20 percent of the patients he or she scopes.
 

The ability to detect adenomas measures the effectiveness of your doctor (if you go through the cleanout, you deserve the very best). So ask your endoscopist what his or her ADR is. If it's below 20 percent, or unknown, find another doctor.

And make sure you get a colonoscopy starting at age 50 (earlier if you have a family history of colon cancer), and then every 10 years after that (more often if you've had polyps detected). Colon cancer has a 90 percent survival rate when caught early. Yet 50 percent of Americans and 70 percent of Canadians don't get colonoscopies when they are supposed to! So scope it out.