Clinical applications of evolutionary medicine principles

This detailed and interesting review from Mandy Azar needs reading through the MORE link.

This thought provoking session on the clinical applications of evolutionary medicine principles began with a case presentation. Dr. Robert Woods presented a case of a woman with a difficult to treat chronic infection of a prosthetic device. Multiple courses of powerful antibiotics and careful deliberation of treatment strategies using evolutionary principles failed to prevent this patient’s demise probably due to inadequate data. Precise analysis later revealed the culprit to be one single organism that probably thrived because of antibiotic resistance and a lack of microbial competition. Dr. Woods astutely demonstrated here, that even with awareness and application of evolutionary principles, there still can be significant challenges in individual clinical cases due to a lack of available evidence-based strategies in evolutionary medicine. He went on to emphasize that as it stands now, there are barriers to translational evolutionary medicine because most evolutionary studies focus on a single evolutionary mechanism in isolation and that often clinical scenarios are more complicated. There is also a dearth of clinical studies looking at evolutionary outcomes. However, he pointed out that such cases serve to illustrate the gaps in our collective knowledge and are useful in teaching and engaging students in evolutionary medicine.

In contrast, when evidence-based evolutionary studies do exist, they can be instrumental to clinicians during the risk vs. benefit decision making process. Dr. Joe Alcock used the topic of opioid treatment strategy to elegantly demonstrate this concept. We learned that opioid treatment has sky rocketed in the U.S. In the past 15 years, partly due to physicians’ knee jerk reaction to patients’ pain complaints. This has lead to undue societal abuse, harm and death. He pointed out that using evidence-based tools, like NNT (# needed to treat) and NNH (# needed to harm), along with the evolutionary perspective of the adaptive nature of pain, can assist clinicians in more judicious opioid prescription practices. The same strategy could be applied to stimulant medications as well. Dr. Alcock also illustrated that evidence-based practices have a lag period of 10-17 years between publication and clinical adoption. He urged that evolutionary medicine can help to speed this process along and provide a framework by which clinicians can confidently apply new evidence-based knowledge.

Dr. Mark Schwartz chose a stimulating interactive presentation to demonstrate how clinician-patient communication can be facilitated and enhanced through evolutionary medicine. Two different simulated patient scenarios were used to illustrate this. First, a patient presenting with low fever and cough, after appropriate history and physical examination, could be given simple evolutionary medicine explanations as to why a fever and cough are adaptive and that sometimes doing less is more. It is important to show compassion and provide instructions, such as rest and fluids, reassuring the patient that her symptoms are just expressions of the body’s natural healing process. The second elderly ‘patient’ presented with vague symptoms of fatigue, generalized aches and pains, and despair from the loss of her friends. She might be comforted and buoyed up by explaining that these are realities of life as we age. In this case, after ruling out any specific disease process, it is useful for the clinician to keep in mind the patient’s life history and the evolutionary theories of senescence including trade offs and the foreseeable changes in mental and physical function that come with advancing age. For clinicians, this will not only prevent excessive testing and unnecessary treatment but will also serve as a vehicle of communication enhancing the sense of wellbeing in the frail geriatric patient.

Next, Dr. Shelley Hwang made a compelling argument for the use of evolutionary medicine research to enhance screening and eliminate the over-diagnosis of cancer. She pointed to the examples of thyroid cancer screening and over diagnosis in Korea and the exploding incidence of DCIS (ducal carcinoma in situ ) in the U.S. that correlated with the increasing number of mammography machines. Dr. Hwang’s reasoning is based on the fact that cancers develop through the process of somatic evolution and that measuring and studying this process may lead to discovery of universal bio-markers. She explained that genetic somatic mutations are a regularly occurring phenomenon and with increasing genetic diversity, there is more susceptibility to natural selection pressures. These mutations can progress to non-deleterious or deleterious states that in many cases may not require treatment. She proposed a novel approach in cancer research insisting that application of ecological and evolutionary principles to guide screening strategies, as in DCIS or Barrett’s esophagus for example, may very well lead to better outcomes. The hope is that by understanding the interactions between tumors and their environments, it will facilitate its application across all cancers.

The last presentation of the session, by Chelsea Landolin, explored the application, advantage and disadvantages of using an evolutionary perspective in the field of nursing. She illustrated this through a case report of a young patient with a host of chronic diseases including schizophrenia who presented in ER in distress. He is evaluated by many different practitioners in nursing from triage, to acute care, to specialized GI and cardiovascular clinical nurse specialists. She points out that nurses can benefit from an evolutionary perspective not only to recognize their patient’s mismatch to their modern environment but also to understand general healing processes. It can also serve to improve communication with healthcare professionals from various disciplines. Nurses play a key role in patient safety, education, healing and comfort. Removing barriers to care might be facilitated by educating nurses in the principles of evolutionary biology.

Despite the late hour, their was an animated Q & A period at the end of the session. The highlight conclusion/ revelations were as follows:

1. Dr. Alcock said: Physicians themselves are agents of natural selection in antibiotic resistance by their prescribing behavior. This must be communicated to clinicians more widely. The public is becoming more aware of the microbiology which in turn may drive physicians to prescribe less antibiotics

2. Dr. Scwhartz reminded us: As physicians we should heed more the adulterated version of the old adage “Don’t just do something, stand there”. This is in reference to using evolution as a guide that can allow confidence and communication when we don’t intervene and let nature take its course.

3. Dr. Hwang made the point that there is intra as well as inter-tumor heterogeneity. She said: ‘There is no point in making the discoveries we’re making in cancer if we are not courageous enough to do something about it”

4. Dr. Stephen Stearns raised the question of ‘what can we do about the problem of physician’s behavior aimed at the good of the individual patient that may be in conflict with what is good for the population at large?’

Several people commented about their concerns that precision medicine may be too targeted and thus leave out a large proportion of the disenfranchised, racially diverse or lower socio-economic sub-groups. The best research and clinical application of evolutionary medicine won’t benefit us if there isn’t basic access to healthcare.