Estimating scenarios for survival time in men starting systemic therapies for castration-resistant prostate cancer: A systematic review of randomised trials

BackgroundWe sought to estimate worst-case, typical and best-case scenarios for survival in men starting systemic therapies for castration resistant prostate cancer (CRPC).MethodsWe sought randomised phase 3 trials of systemic therapies for CRPC and recorded the following percentiles (represented scenario) from Kaplan–Meier overall survival (OS) curves: 90th (worst-case), 75th (lower-typical), 50th (median), 25th (upper-typical) and 10th (best-case). We determined the accuracy of using simple multiples of the median OS to estimate the other selected percentiles from each curve: 0.25 for 90th, 0.5 for 75th, 2 for 25th and 3 for 10th. Estimates were deemed accurate if within 0.75–1.33 times the actual value.FindingsWe reviewed 23 trials (13,909 men) with 48 treatment groups including 28 of chemotherapy, and three of novel hormonal agents. In trials of first-line docetaxel, the mean (interquartile range) for median OS was 19 months (17–20), and for each scenario was: worst-case 7 months (6–8); lower-typical 12 months (11–13); upper-typical 29 months (27–31); and best-case 40 months (34–44). For trials of novel hormonal agents after chemotherapy the mean values were: median OS 17 months, worst-case 5 months, lower-typical 9 months, upper-typical 24 months and best-case not reported. Simple multiples of the median gave accurate estimates of the worst-case scenario in 72% of OS curves, lower-typical in 89%, upper-typical in 84% and best-case in 84%.InterpretationSimple multiples of the median OS from randomised trials provided accurate estimates of worst-case, typical and best-case scenarios for survival time in men starting systemic therapies for CRPC.