Estimating typical, best-case and worst-case scenarios for survival time in men starting systemic therapy for castrate-resistant prostate cancer: A systematic review of randomized trials — YRD
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Estimating typical, best-case and worst-case scenarios for survival time in men starting systemic therapy for castrate-resistant prostate cancer: A systematic review of randomized trials (#19)

Timothy West 1 , Belinda Kiely 1 2 3 , Martin Stockler 1 2 3
  1. Sydney Medical School, The University of Sydney, NSW, Australia
  2. National Health and Medical Research Council Clinical Trials Centre, University of Sydney, Camperdown, NSW, Australia
  3. Department of Medical Oncology, Sydney Cancer Centre, RPA and Concord Hospitals, Camperdown, NSW, Australia

Background/significance:
Recent advances in treatment have substantially improved the overall survival (OS) of men with castration resistant prostate cancer (CRPC).

Objectives:
To summarise data on OS from pertinent randomised trials and to determine the accuracy of using simple multiples of the median OS to estimate scenarios for survival preferred by patients wanting prognostic information.

Methods:
We sought randomized phase 3 trials of first and second-line systemic therapies for CRPC and recorded the following percentiles (represented scenario) from Kaplan Meier curves for OS: 90th (worst-case), 75th (lower-typical), 50th (median), 25th (upper-typical) and 10th (best-case). We also determined the accuracy of using simple multiples of the median survival to estimate the other percentiles from each curve (represented scenario): 0.25 for 90th (worst-case), 0.5 for 75th (lower-typical), 2 for 25th (upper-typical) and 3 for 10th (best-case). Estimates were deemed accurate if within 0.75 to 1.33 times the actual value.

Results:
We found 23 trials with 13909 men including 15 trials of chemotherapy and 3 trials of novel anti-androgens. For first-line docetaxel trials, 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 novel anti-androgens 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 has not been reached. Across all trials, simple multiples of the median OS 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%.

Conclusion:
Simple multiples of the median provided accurate estimates of other percentiles from the corresponding survival curve that are useful for describing the worst-case, typical range, and best-case scenarios for survival to men starting contemporary systemic therapies for CRPC.