Quality-adjusted survival comparison between androgen deprivation with radiation therapy versus radiation therapy alone for locally advanced prostate cancer: Decision analysis from RTOG 85-31 trial.

Abstract

265 Background: Radiation Therapy Oncology Group (RTOG) trial 85-31 has shown that addition of androgen deprivation therapy to radiation therapy (RT+ADT) for patients with locally advanced prostate cancer benefits local control and progression-free survival compared to RT alone. However, the survival gain may be diluted with increased toxicity of hormone manipulation. There is a need to develop new decision analysis methods to incorporate survival time and quality of life (QoL) adjusting for various health states and persistent complications. Methods: We previously developed “quality-adjusted survival analysis using duration” (QASAD) and “quality-adjusted survival analysis using probability” (QASAP) to estimate quality-adjusted survival time. The QASAD uses the median duration in each state to weight the utilities, while the QASAP uses the proportional probability of being in each state for weighting. The survival and complication rates of RTOG 85-31 were reconstructed based on published Kaplan-Meier survival curves, and the utility values for states were obtained from the literature. Probabilistic sensitivity analysis was applied using Monte Carlo simulation with 1000 simulated samples. Results: QASAD and QASAP showed that the quality-adjusted life year (QALY) values in RT+ADT were generally higher than those in RT. In probabilistic sensitivity analysis, QASAD resulted in 4.93 (95% bootstrapped confidence interval [CI] = 4.12 to 5.71) for RT and 5.60 (95% CI = 4.30 to 6.48) for RT+ADT. QASAP resulted in 4.85 (95% CI = 4.16 to 5.39) for RT and 4.96 (95% CI = 3.73 to 5.78) for RT+ADT. Conclusions: The decision analyses showed that RT+ADT provided slightly better quality-adjusted survival outcome after treatment than RT alone. The QASAD and QASAP methods may help the decision of optimal treatment balancing between survival gain and unfavorable quality of life. [Table: see text]