Can Patients Understand the Concept of Overdiagnosis?

Kenneth W. Lin, MD, MPH


April 07, 2015

Editorial Collaboration

Medscape &

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Hi, everyone. I am Dr Kenny Lin. I am a family physician at Georgetown University School of Medicine in Washington, DC, and I blog at Common Sense Family Doctor.

In a previous commentary, I touched briefly on the notion of overdiagnosis. This is a difficult concept for patients and physicians to grasp. It refers to making a diagnosis that is ultimately not necessary because the patient would never have suffered any symptoms or death from the disease. Overdiagnosis usually occurs when physicians screen a patient for a disease such as cancer in an effort to detect it at an early stage when it may be more amenable to treatment. Unfortunately, cancer screening often detects clinically insignificant tumors for which the treatment is worse than the disease.

Prostate cancer is the poster child for overdiagnosis. Until we started widely screening for it with the prostate-specific antigen test, it was considered a disease with a uniformly bad prognosis. These days, most men diagnosed with prostate cancer choose surgery or radiation therapy, which often lead to bothersome side effects.

Autopsy studies of men who died from conditions other than cancer have found that prostate cancer is extremely common. In fact, a majority of men in their 60s and 70s will have pathologic evidence of prostate cancer, but only 1 in 30 men will actually die from the disease.[1] Studies now estimate that 1 in 2 prostate cancers, 1 in 3 breast cancers, and 1 in 5 lung cancers are most likely overdiagnosed.[2]

Decision Aids for Shared Decision-Making

In my opinion, doctors are not doing nearly enough to inform patients about the possibility of overdiagnosis, and we really need to do more. One survey[3] of people aged 50-69 years found that only 9.5% of patients were told about the possibility of overdiagnosis when cancer screening was discussed. Given the results of another survey[4] that shows that patients' tolerance levels for overdiagnosis can vary widely, it is absolutely essential that we include a discussion of overdiagnosis in shared decision-making about cancer screening.

Doctors may object that the concept of overdiagnosis is challenging for physicians to understand; thus, patients could not possibly grasp the idea in a short discussion. This is where a good decision aid can come in. A randomized controlled trial[5] published in The Lancet found that women who were given a decision aid that contained information about overdiagnosis in mammography had more knowledge about screening outcomes and were more likely to make a decision based on their personal preferences than women who were given a decision aid that did not contain information about overdiagnosis. Although this decision aid is not available online, I found another good decision aid[6] from the Public Health Agency of Canada that I plan now to use with my patients. I plan to use this whenever I discuss mammography in women aged 40 years and older, and I hope that you will consider doing so too.

This has been Dr Kenny Lin for Medscape Family Medicine. Thank you for listening.


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