Colonoscopy is best screening test we have for colon cancer


DEAR DR. ROACH: My husband, who is 73 and in good health otherwise, had a colonoscopy in the summer of 2012 and was told that because no polyps or any problems were found, he did not need another test for 10 years. This October, he was diagnosed with stage 4 colon cancer, which has spread to the abdomen and omentum. He also had seven polyps removed during his latest examination.

My question is, How likely is it that such a virulent cancer could grow in such a short time? I would be resigned to the diagnosis if I didn’t feel that something was missed in the initial exam. Also, I had a colonoscopy done by the same doctor this summer and also was told that I need not come back for 10 years. Should I be concerned? — H.B.

ANSWER: I am very sorry to hear about your husband. What happened is very unusual. All guidelines agree that in a person with a normal colonoscopy, a repeat in 10 years is recommended. A repeat in five years would have been recommended if a low-risk polyp had been found, earlier with high-risk or multiple polyps. I haven’t personally seen a case like your husband’s, where an advanced cancer presents less than 10 years after a normal colonoscopy. This should happen in fewer than one in a thousand people.

There are several reasons why it can happen. The most important is that even a properly done colonoscopy misses polyps. Very small polyps (less than 5 mm) can be missed 26 percent of the time, but large polyps (greater than 10 mm) are missed only 2 percent of the time. Although the colonoscopy is the best screening test we have for colon cancer, it isn’t perfect. It’s also possible that he just had a very fast-growing cancer.

While I understand your concern about getting yourself an earlier repeat colonoscopy, your risk is very small, and if you trust the doctor who did the colonoscopy, you should get your repeat in 10 years.

DEAR DR. ROACH: I recently was diagnosed with a 40 percent to 50 percent blockage in my left carotid artery. I am an 85-year-old woman and not in good health. I have A. fib, a pacemaker, high blood pressure and a very weak heart. I go to a cardiologist, and he always talks about surgery. I don’t think I could go through another surgery, much less test after test. I feel I should just let it alone, but would love to have your input. — L.H.

ANSWER: The two carotid arteries supply your brain with blood. Blockages in these arteries are a major cause of stroke and TIA (transient ischemic attack, very similar to a stroke but lasting less than 24 hours). There has been debate about the proper treatment for blockages, and current recommendations are based on sex, degree of blockage and whether there are any symptoms. Men are at higher risk, and surgery has been shown to benefit men with no symptoms and blockages of 60 percent to 99 percent. Very few authorities would recommend surgery to women unless they had a blockage above 60 percent to 70 percent, were generally healthy and where the risk of stroke or death for the surgery was less than 3 percent. Because your blockage is only 40 percent to 50 percent and you have some other medical issues, I generally would not recommend surgery for someone in your situation.

Medical management should include aspirin or other antiplatelet medication, a statin drug and careful control of blood pressure. I would add that a healthy diet certainly will help, and quitting smoking and control of diabetes is absolutely necessary for smokers and diabetics, respectively.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to [email protected] or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Health newsletters may be ordered from

(c) 2014 North America Syndicate Inc.

All Rights Reserved