According to an article in JAMA Internal Medicine, patients are not being properly informed about the possibility of overdiagnosis from screening programs. In addition, many of those patients wouldn't participate in screening programs if that overdiagnosis rate was too high.
"The consequence of overdiagnosis is overtreatment--surgery, chemotherapy, or radiation--that provides the patient no benefits, but only adverse effects," wrote Odette Wegwarth, Ph.D., and colleague Gerd Gigerenzer, Ph.D, of the Max Planck Institute for Human Development in Berlin. "For instance, for every 2000 women attending mammography screening throughout 10 years, 1 less dies of breast cancer. Concurrently, approximately 10 women with pseudodisease receive a diagnosis of breast cancer and are unnecessarily treated."
So, they asked, are patients being informed about overdiagnosis when they discuss cancer screening with their physicians? The answer, they report, is no.
The two conducted an online survey of 317 men and women in the U.S. between the ages of 50 and 69 to find out how many patients were informed about overdiagnosis by their physicians. Mammography was the most common of the screening exams reported by women, while colonoscopy and PSA testing were the most common reported by men.
The survey found that only 30--less than 10 percent--of the respondents discussed the possibility of overdiagnosis and overtreatment from cancer screening with their physicians. Of those 30, nine said their physicians quantified the risk of overdiagnosis (although the numbers provided by the respondents were generally overestimates or underestimates of those risks, the authors reported).
A slight majority of the respondents (51 percent) said they would not start a screening program that resulted in more than one overtreated person per life saved. Fifty-eight percent said they would continue to participate in a program if they learned that the program resulted in 10 overtreatments per one life saved. However, 69 percent said they wouldn't start that a screening program if that program resulted in more than 10 overtreatments per one life saved.
In an accompanying editorial H. Gilbert Welch, M.D., said that while patients usually understand that medical treatment offers the possibility of both benefit and harm, they've been "taught to think differently about screening. There are no harms. It's always good to know. It is just about getting information. Of course you want it. It is a brain-dead decision."
The truth is "more nuanced," he wrote. "There are benefit and harms to consider in screening--just as there are in treatment. There's no longer any argument about this."
Welch also wrote that while he doesn't know how accurate the Wegwarth and Gigerenzer survey is, he does know that the issue "should be studied further. The potential implications for screening practice are huge."
To learn more:
- read the article in JAMA Internal Medicine
- see the editorial by H. Gilbert Welch, M.D