Skin Cancer Diagnosis: Shining Light into Dark Places

Commentary in Acta. Full (open access) paper here

Frank Davidoff, the celebrated US physician, has a telling metaphor for medical competence: he likens it to Dark Matter, the material physicists think makes up most of the Universe, and about which we know so little (1). Clinical competence would, in this analogy, be the material that literally holds and binds clinical practice – our professional lives – together. How come we know so little about it?

Literary fiction of course has plenty of bad doctors, but frequently they appear to be evil rather than merely clinically indifferent. Dr Watson, Sherlock Holmes’ fictional friend and narrator, is of course a general practitioner, and whereas we are unlikely to admire his intellectual abilities, we assume he is ‘sound’ in his professional life. This lack of judgement or curiosity about the abilities of individual physicians is how­ever widespread in the real world too. Within the UK national health service (NHS), doctors, it sometimes seems, are viewed as interchangeable units, who possess skills defined at a lower bound in terms of training and certification, and who can be deployed as though they were machine tools in an industrial factory. Many of us think otherwise, believing that there is considerable variation in clinical competence (2). Hidden in plain sight perhaps, but present.

Different types of evidence attest to this variation in performance. Most doctors when they or their immediate families are ill, choose who to consult with great care. Ever since the seminal work of Wennberg (3), we know that clinical decision-making by doctors is far from uniform or consistent, and that such differences account for much of the variance in health care costs. We do not understand all the reasons for clinical heterogeneity – financial biases are likely to play a role – but from the patient’s perspective, medical advice is heavily dependent on who you consult. Finally, given what we know about expertise in general – in fields as diverse as musicianship, sport or academic ability – it would be bizarre if differences in ability were not the norm rather than the exception (4, 5).

Post by Jonathan Rees

Clinical academic and skin watcher at the University of Edinburgh

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