Morning Rounds: How reliable is a colonoscopy?

(CBS News) CBS News chief medical correspondent Dr. Jon LaPook and CBS News contributor Dr. Holly Phillips joined "CBS This Morning: Saturday" to discuss the major medical stories of the week.

Close to 150,000 Americans die every year of colorectal cancer, the second leading cause of cancer deaths. A new study in the New England Journal of Medicine says that getting a colonoscopy every 10 years can prevent 40 percent of those cancers.

Colonoscopies are supposed to catch polyps and allow doctors to remove them before they turn cancerous. Polyps shaped like mushrooms are lot easier to find, but many people have flat polyps, which are not only more likely to be missed but more likely to be cancerous.

LaPook told the "CBS This Morning: Saturday" co-hosts that the study provided good feedback about colonoscopies, but, at the same time, it pointed out that the procedures are not perfect and that doctors can do even better.

"Studies do suggest that some gastroenterologists simply go too quickly and they're not looking carefully enough," he said. "The good news is that gastroenterology societies are really laying down criteria now saying, 'Look, you've got do it this way,' and I think that people are really starting to realize this is a problem."

Also, federal health officials released new estimates of the number of Americans who get sick from bacteria that are resistant to antibiotics. At least 2 million people are infected with the so-called superbugs each year, and over 20,000 die. The Centers for Disease Control and Prevention said these numbers are probably conservative and that resistant strains of bacteria are a major public health threat.

Phillips told the "CBS This Morning: Saturday" co-hosts that this problem is happening because people are overusing antibiotics. She said that it is important to know when you actually need an antibiotic and when the drug will not help.

"Bacteria are really smart; for being so small, they're really, really smart. If you expose the bacteria to the same antibiotics over and over, new strains develop that cannot be killed by those antibiotics; they are resistant," she said. "This is a natural process. We expect it to happen, we expect these bacteria to become resistant, but it's happening faster than ever right now because we're overusing antibiotics, and it's happening so fast we can't create new antibiotics fast enough to fight off these superbugs."

For Dr. Jon LaPook and Dr. Holly Phillips' full roundup on this week's medical stories, watch the video in the player above.

Check out more from Morning Rounds with Dr. LaPook