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Updated: Oct 20, 2026

Evaluating the Effectiveness of Cancer Drug Sensitization In Vitro and In Vivo
Published on: February 5, 2015
Why post-progression survival and post-relapse survival are not appropriate measures of efficacy in cancer randomized
Xabier García-Albéniz1, Joan Maurel, Miguel A Hernán
1Department of Epidemiology, Harvard School of Public Health, Boston, MA.
Abstract:
Comparisons of post-relapse survival (PRS) and post-progression survival have been used to measure efficacy in some cancer clinical trials. These comparisons are an attempt to account for second-line therapies and to identify benefits that do not translate in longer overall survival. However, the use of PRS comparisons can be misleading (either a longer or shorter PRS may indicate a benefit, depending on the circumstances) and can result in biased estimates (because of selection). Here, we describe the problems surrounding PRS comparisons and propose alternative approaches to deal with non-randomized therapies administered after progression to the experimental treatment.
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