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Feature Essay

The historical rise of “overdiagnosis”—an essay by Scott Podolsky

BMJ 2022; 378 doi: (Published 22 July 2022) Cite this as: BMJ 2022;378:o1679

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Does thinkiong about "overdiagnosis" help with shared decision-making about screening?

Dear Editor
Podolsky’s [1] historical account of overdiagnosis is welcome, reminding us that, like any medical intervention, diagnosis can produce harms as well as benefits. But the essay fails to highlight a key problem: “overdiagnosis” implies that there is a “just right” amount of diagnosis, yet this is a hopelessly slippery amount to pin down because it depends on value judgements. “Just right” is only meaningful in the specific context of population-level decisions taken by health economists and politicians, decisions that need updating as new evidence emerges. As a doctor talking with someone who feels healthy, aiming to reach a shared decision about screening for conditions like hypertension and “early cancer” that may cause harm in future, I used to emphasise that there is no right answer. My task was to help “the patient” reach an evidence-informed decision that reflects their own values; my own personal enthusiasms and scepticisms constituted obstacles to be recognised and circumnavigated, as Podolsky recommends.
Within these shared decision-making conversations, the difficulty is that it is easier to think about a terrible although unlikely thing, like cancer or a stroke, than it is to think about less dramatic but much likelier things like the potential harms of diagnosis. The concept “overdiagnosis” has never helped me overcome this difficulty, and trying to think about an “overdiagnosed” individual is actively misleading, clashing with what we know about the irreducible uncertainty of an individual’s future. The challenge is to talk with each person about the uncomfortable fact that despite robust evidence about “people like them”, we have no crystal ball to tell us whether their particular early diagnosis will lengthen their life, cause them harms, or both.

1. Podolsky, S. The historical rise of “overdiagnosis”. BMJ 2022;378:o1679

Competing interests: No competing interests

04 August 2022
Louisa Polak
Retired GP and visiting researcher
Primary Care Unit, University of Cambridge
Bury St Edmunds