Background: Androgen deprivation therapy in addition to radiation therapy (RT + ADT) has shown benefits in local control and progression-free survival compared with RT alone for patients with locally advanced prostate cancer in Radiation Therapy Oncology Group 85-31. However, the survival gain may be diluted with increased toxicity of ADT. The aim of the study is to compare quality-adjusted life years (QALYs) values between two groups.
Methods: We developed "quality-adjusted survival analysis using duration" (QASAD) and "quality-adjusted survival analysis using probability" (QASAP) to estimate the quality-adjusted survival time. The QASAD uses the median duration in each health state to weight the utilities, whereas the QASAP uses the proportional probability of being in each state for weighting. The survival and complication rates were reconstructed based on published Kaplan-Meier survival curves, and the utility values for states were obtained from the previous literature.
Results: QALYs values for RT + ADT were generally higher than those for RT. The QASAD resulted in a QALY value of 4.93 [95% bootstrapped confidence interval (CI) = 4.12-5.71] for RT and of 5.60 (95% CI = 4.30-6.48) for RT + ADT. QASAP resulted in a QALY value of 4.85 (95% CI = 4.16-5.39) for RT and 4.96 (95% CI = 3.73-5.78) for RT + ADT.
Conclusions: We showed that RT + ADT provided slightly better quality-adjusted survival outcome than RT alone. The QASAD and QASAP methods may help the decision of optimal treatment balancing between survival gain and unfavorable quality of life.
Keywords: Decision support techniques; Quality of life; Quality-adjusted life years; Quality-adjusted survival analysis; Survival analysis.