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Interpreting Treatment Effects Using Posterior Probabilities: A Bayesian Reanalysis of 230 Phase III Oncology Trials
Alexander D Sherry1,2, Pavlos Msaouel3,4, Gabrielle S Kupferman1
1Division of Radiation Oncology, Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX.
Posterior probability analysis of phase III oncology trials reveals discrepancies with traditional P-value thresholds. Bayesian models offer unique interpretative value for clinical relevance, improving trial interpretation.
Area of Science:
- Oncology
- Biostatistics
- Clinical Trials
Background:
- Traditional oncology trials use P-value thresholds for superiority, which are often misinterpreted.
- Posterior probability offers a direct estimation of hypothesis probability, enhancing interpretation.
Purpose of the Study:
- To reanalyze phase III oncology trials using posterior probability.
- To benchmark posterior probability against standard statistical significance interpretation.
Main Methods:
- Reconstructed outcomes from 194,129 patients across 230 phase III oncology trials.
- Calculated posterior probabilities for treatment effect using various priors and clinically relevant effect sizes, including minimum clinically important difference (MCID).
Main Results:
- Trials deemed superior by P-values showed >90% probability for marginal benefits (HR < 1).
- Fewer positive trials met the ASCO (HR < 0.8) or ESMO (HR < 0.64) MCID thresholds with >90% probability.
- Some trials not deemed superior still had >90% probability for marginal benefits.
Conclusions:
- Bayesian models and posterior probability offer unique interpretative value in oncology trials.
- Posterior probability can bridge the gap between refuting the null hypothesis and identifying clinically relevant effects.
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