Patients' preferences for delaying metastatic castration-resistant prostate cancer: Combining health state and treatment valuation

Purpose: Men with castration-resistant prostate cancer (CRPC) experience disease progression at different rates. The purpose of this study was to quantify the strength of patient preferences for delaying prostate cancer progression utilizing a discrete choice experiment (DCE) and valuing 3 health states in the continuum of CRPC.

Patients and methods: Men with CRPC, recruited from US patient panels, completed a cross-sectional web-based survey. The survey consisted of vignette-based time trade-off and a DCE designed to quantify patients' willingness to pay to delay metastatic CRPC. Three health states were presented: (1) living with non-metastatic castration-resistant prostate cancer (nmCRPC) (2) living with metastatic CRPC (mCRPC) before chemotherapy, and (3) living with mCRPC either on or after chemotherapy. The DCE consisted of 15 hypothetical choices with attributes characterizing CRPC (pain, fatigue, out of pocket cost, dosing, and time until cancer metastasizes). Patients' willingness to pay for changes in each attribute were derived.

Results: A total of 176 patients with CRPC were surveyed (mean age: 64.2 years; 74% nmCRPC). Patients valued the nmCRPC health state (0.865) significantly higher than mCRPC before chemotherapy (0.743) or mCRPC on or after chemotherapy (0.476), both P < 0.001. In the DCE, patient treatment valuation was most affected by increasing the number of months until cancer metastasized; patients were willing to pay an additional $682 per month to delay time to metastases from 6 to 24 months (95% Confidence Interval: $387-$977) and additional $1,041 per month to delay time to metastasis to 48 months (95% Confidence Interval: $591-$1,490).

Conclusions: The results of this study demonstrated men with CRPC place significant value on delaying metastases. This study represents the first time 2 stated preference methods, time trade-off and DCE, were used together to understand patients' preferences and valuation of health states in CRPC.