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.
What's new? Post relapse survival (PRS) and post progression survival have been used to measure efficacy in some cancer clinical trials. PRS comparisons between the experimental and control groups are an attempt to account for second-line therapies or identify benefits that don't translate in longer overall survival. However, the authors argue, the use of PRS comparisons can be misleading (either a longer or shorter PRS may indicate a benefit, depending on the circumstances) and result in biased estimates. They describe the problems surrounding PRS comparisons and propose alternative approaches to deal with the additional use of non-randomized therapies in case of progression.