Clinical Trials Meeting
Deborah Ashby
(Queen Mary College, London )
"`Casting a Sceptical Eye over the Data': Implementing Bayesian Data
Monitoring in Cancer Clinical Trials"
Synopsis: Many clinical trials organisations use regular interim
analyses to monitor the accruing results in large clinical trials.
Classical rules, such as the group-sequential procedures of Peto,
O'Brien and Fleming or Pocock have traditionally been based on
P-values. However, none of these rules formally assess the impact that
the results of a clinical trial might have on clinical practice. Thus
a trial might be terminated early because of apparent treatment
benefit, but fail to influence future clinicians to modify their
future treatment policy. Bayesian rules have been proposed that have
the potential to overcome these difficulties (Freedman, Spiegelhalter
and Parmar, Statistics in Medicine, 1994). Like many Bayesian
techniques, they were originally presented as reanalyses of trials
that have already been published. They are now being used `live'
(Fayers, Ashby and Parmar, Statistics in Medicine, 1997). We present
details of their implementation in a trial of surgery with and without
pre-operative chemotherapy for oesophageal cancer. Practical issues
encountered will be discussed, including the choice of prior
distribution and `clinically relevant' values for use in monitoring,
and presentation of ideas to clinical members of the data monitoring
committee. As one clinician put it `It's just casting a sceptical eye
over the data'.
Date & Time
Thursday 22nd April at 5:30 pm
Place
Lecture room E (level 6) Boyd Orr building, University of Glasgow
Refreshments
There will be tea and biscuits served from 5:00 pm.
Enquiries
Marian Scott 0141 330 5125
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Dr. Marian Scott [log in to unmask]
Department of Statistics www.stats.gla.ac.uk/~marian
University of Glasgow Phone: +44(0) 141 330 5125
Glasgow G12 8QW Fax: +44(0) 141 330 4814
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