I would agree in principle with Dave Sackett's comments so long as the
clinicians decision re whether the intervention is helpful / harmful is
based upon evidence rather than intuition.
One example that is relevant to my practice is the use of anthracylines
as adjuvant therapy for breast cancer. There is evidence from the latest
EBCTG overview that there is a small survival advantage for
anthracycline containing regimens compared to other regimens. However,
clinicians may either be unaware of,or have preconceived ideas re the
use of anthracyclines.
These views are likely to influence their decision to enter patients
onto adjuvant breast cancer trials if the standard arm contained an
anthracycline. This may not be particularly evidence based
Peter Ellis
Dave Sackett wrote:
>
> dr simon's interpretation of the uncertainty principle is not the one
> that's held here in oxford at the clinical trials service unit where
> richard peto works.
>
> the problem being addressed here is not adherence to entry criteria but
> the thorny issue we clinicians and researchers face when grappling with
> the ethics of human experimentation.
>
> briefly, it suggests that whether a specific patient who already fits the
> entry criteria for a trial ought to be entered into the trial depends (in
> addition to other key elements such as informed consent) on the state of
> certainty/uncetainty in the mind of the admitting clinician about whether
> the intervention under study would be helpful or harmful.
>
> if the clinician is convinced that the intervention would benefit this
> particualr patient, the patient is not randomised, but is offered the
> intervention outside the trial.
>
> if the clinician is convinced that the intervention would harm this
> particular patient, the patient is not randomised, but is informed and
> advised against the intervention.
>
> it is when the clinician is uncertain whether the patient would benefit
> from the intervention that informed consent is requested and the patient
> is randomised.
>
> as a clinician-trialist involved one way or another in about 200 trials,
> it's my experience that the uncertainty principle makes it far easier on
> both sides of the protocol (we avoid the perplexing and [for most of us,
> incorrect] arguments about the need for "equilibrium", on the one hand,
> but are free to exercise clinical judgement when we're certain a patient
> will benefit/ be harmed from the treatment under study).
>
> (the randomisation process often involves "minimisation" for balance as
> well)
>
> i hope that this clarifies the discussion.
>
> cheers
> dls
>
> ............................................................................
> Prof David L. Sackett
> Director, NHS R&D Centre for Evidence-Based Medicine
> Consultant in Medicine Editor, Evidence-Based Medicine
> Nuffield Department of Medicine, University of Oxford
> Level 5, John Radcliffe Hospital, Oxford OX3 9DU, England
> Phone: +44-(0)1865-221320 Fax: +44-(0)1865 222901
> Email: [log in to unmask] WWW: http://cebm.jr2.ox.ac.uk
>
--
Peter Ellis MBBS FRACP MMed(Clin Epi)
Research Fellow
Dept Medical Psychology Royal Prince Alfred Hospital
Dept Cancer Medicine Sydney University
Ph: 61 2 9515 7618
Fax: 61 2 9515 5697
email: [log in to unmask]
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