50% of what you are taught is wrong…

Glass Half Full by baileyraeweaver courtesy of Flickr Creative Commons.
Photo by baileyraeweaver courtesy of Flickr Creative Commons.

There is a phrase in medical education which often gets aired at the welcoming lecture to medical school:

“50% of what we teach you over the next five years will be wrong, or inaccurate. Sadly, we don’t know which 50%”

Quite why those welcoming students to a rigorous, physically and mentally demanding degree course would openly admit that 50% of what is on the syllabus is likely to be wrong is not clear.  Is it simply a reflection on their own career paths, and a lament for wasted hours of poring over books? a thinly veiled plea to the students not to take learning every cause and sign of clubbing too seriously, and ensure that they also enjoy their studies? or is this phrase a recognition of the ever advancing nature of medical knowledge.  If medical advances keep pace with Moore’s Law of the computing world.

This phrase has been called to mind a few times whilst reading through papers in the PMJ recently.  There is a couplet of papers looking at Eosinophilic Oesophagitis – a disease entity that has only really come to be widely recognised in the past decade or so ( in my medical school general text it garners a mere 5 or 6 sentences ) having been described first in 1978. One paper outlines the presentation and pathogenesis and the other covers the investigation and management of the condition. The presentation of eosinophilic oesophagitis can be varied, and difficult to tease apart from other conditions that can demonstrate very similar characteristics, and yet have a significantly different underlying pathology and requirement for treatment.

This overlap of presentations is not exclusive to eosinophilic gastroenteritis. As we understand diseases in greater and greater detail – we begin to recognise that the labels of the past may not be as accurate or helpful as we once thought.  In respiratory medicine, the two giants of obstructive airways disease – Asthma and COPD are becoming ever more blurred – as we see ever more advanced treatments helping in sub-populations, often determined by the inflammatory cells which inhabit the airways.  With this detail of understanding available more routinely to clinicians, the old labels become less helpful. A paper in Thorax recently called for clinicians to consider scrapping the terms Asthma and COPD – a sign perhaps of things to come in the post-genomic era of modern medicine, where we are more and more exact in our definitions of disease, partly because the treatments we are developing are more and more exact

Lung cancer is another field that is changing at a blistering pace. A recent republished article in the PMJ questioned the need for even asking if patients have smoked when considering their treatment for lung cancer.  The thesis is that smoking doesn’t correlate well with the driver mutations found in lung cancer genotypes, and therefore can’t predict suitability for, or response to treatment. This isn’t to say that smoking isn’t an important factor in the development of lung cancer – but it demonstrates how our understanding of a disease process has been revolutionised by technology which a few years ago was far out of reach, and is now routine practice.

Indeed – it will not be long before personalised therapies for different diseases will be based not on crude groupings like age, sex, or smoking habits, but will be guided by genomic studies of target organs – the age of truly personalised medicine is very nearly upon us.

Medical progress then is unrelenting, and all of what went before was wrong or useless.  Well, not exactly.  Foucault – a French Philosopher who considered medicine in some detail- used the term episteme to describe the unconscious structures underlying the production of knowledge in any given time and place.  So we can only develop knowledge which is available to us at the time we are studying.  Moreover, as new technologies reveal more about the nature of disease, and challenge received wisdoms of old, we are slowly changing the episteme in which we live, and enable further discoveries in diverse fields to be made.

As I read general medical journals, and discover new areas of science, medical practice and read about ‘new’ diseases or therapies, the papers which erode my ignorance reassures me that the medical world doesn’t stay still, but that the relentless pursuit of new knowledge allows us to bring greater understanding to the illnesses that afflict the patients we see day to day.

By appreciating that we can only be taught what is known when we are in medical school, the 50% rule is actually a reassuring acceptance of reality, and I think, a call to lifelong learning.


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