Adjusting Survival Time Estimates to Account for Treatment Switching in Randomized Controlled Trials—an Economic Evaluation Context: Methods, Limitations, and Recommendations

Background. Treatment switching commonly occurs in clinical trials of novel interventions in the advanced or met-astatic cancer setting. However, methods to adjust for switching have been used inconsistently and potentially inappropriately in health technology assessments (HTAs). Objective. We present recommendations on the use of methods to adjust survival estimates in the presence of treatment switching in the context of economic evaluations. Methods.We provide background on the treatment switch-ing issue and summarize methods used to adjust for it in HTAs. We discuss the assumptions and limitations associ-ated with adjustment methods and draw on results of a sim-ulation study to make recommendations on their use. Results. We demonstrate that methods used to adjust for treatment switching have important limitations and ofte