Health State Utility Valuation in Radio-Iodine Refractory Differentiated Thyroid Cancer (RR-DTC)

Abstract

Objectives: The study is designed to capture health related quality of life (HRQL) weights for radioiodine refractory differentiated thyroid cancer (RR-DTC) health states. Current treatment options for RR-DTC are limited, with generally poor prognosis. As new treatments emerge for RR-DTC, associated cost-effectiveness evaluations require appropriate preference-weighted HRQL values. Methods: Vignette descriptions for RR-DTC treatment response and adverse event (AE) health states were informed by qualitative work conducted with RR-DTC patients in the US and interviews with 6 clinicians and nurses in the UK and US with RR-DTC treatment experience. Health states included: stable disease, treatment response, progressive disease, stable + grade III diarrhea, stable + grade III fatigue, stable + grade III hand foot syndrome (HFS), stable + grade I-II alopecia. The vignettes were reviewed by the UK and US clinical experts and piloted with UK general public participants in cognitive debrief interviews (n= 5). All vignettes were valued by a UK general public sample (n= 100) using a visual analogue scale (VAS) rating and time trade off (TTO) interview. Data were analysed using descriptive and regression methods. Results: The mean TTO health utilities for RR-DTC states ranged from treatment response (0.86; 95% confidence intervals (CI) 0.83,0. 89); through stable disease (0.80; CI 0.77, 0.84); to progressive disease (0.50; CI 0.45, 0.56). AEs had a significant effect also (stable + grade I-II alopecia (0.75; CI 0.71, 0.79), + grade III fatigue (0.72; CI 0.67, 0.77), + grade III HFS (0.52; CI 0.46, 0.58), and + grade III diarrhea (0.42; CI 0.36-0.48). Conclusions: TTO utilities from this vignette study show clear differentiation between RR-DTC states. The order and magnitude of HRQL impact demonstrated by the utility values reflected clinical opinion and elicited VAS scores. The values reported in this study are suitable for use in cost-effectiveness evaluations for new treatments in RR-DTC.