Rumor control: How to battle online misinformation

E-mails touting false health claims are common, and it can be hard to debunk them to worried patients. One doctor decided the best way to fight a viral e-mail was by creating his own.

By John McCormack, AMNews correspondent. March 17, 2008.

For many years, several patients each week have come to William H. Parker, MD, to request a CA-125 blood test, or to inquire about scheduling a hysterectomy based on the results of a prior CA-125.

When this happens, Dr. Parker takes a deep breath -- then reels off a lengthy explanation of the test's shortcomings as a screening tool for ovarian cancer. He tells them that the test, which produces an inordinate number of false-positives, should not be used to make important surgical and treatment-related decisions.

But despite the fact that Dr. Parker is a clinical professor at the David Geffen School of Medicine at the University of California at Los Angeles, chair of the Dept. of Obstetrics and Gynecology at Saint John's Health Center in Santa Monica, Calif., an adviser to a number of scholarly journals, and the author of A Gynecologist's Second Opinion: The Questions and Answers You Need to Take Charge of Your Health, he still has to pull out all the stops to get his patients to agree.

Why does it take a Clarence Darrow-like argument to get patients to buy into Dr. Parker's position?

These women wholeheartedly believe in the CA-125 test to screen for ovarian cancer because they read about it in an e-mail, one that has been circulating since 1998. The woman who wrote it -- Carolyn Benivegna of Novi, Mich. -- sent out a revised version two years later, which explained that although the test was right for her, it might not work for everyone, and should be only one part of a diagnostic regimen.