P01.112 The challenge of health utility values for glioblastoma patients with long-term survival

Abstract

Glioblastoma (GBM) is the most aggressive form of primary brain cancer in adults. The EF-14 trial was the first randomized controlled trial to report a GBM survival rate greater than 10% at 5-years. In order to estimate the economic impact of new treatments, the quality-adjusted life year (QALY) has been developed and is widely used in health economic literature. For the assessment of QALYs, health utility values are needed. Utilities are preference weights for health states and are measured on a cardinal scale of 0–1, with 0 indicating death and 1 indicating full health. They are determined either through direct elicitation methods (e.g. time trade-off, standard gamble) or generic preference-bases measures like Health Utilities Index (HUI), Short form 6D (SF-6D) or the EuroQoL-5D (EQ-5D). However, in oncology they do not account for patients with long-term survival. This approach may understate QALYs, as a patient alive 5-years after diagnosis will be assigned the same utility value as a patient recently diagnosed.We performed a comprehensive review of the published literature regarding health utility values in GBM patients through a Pubmed search using “glioblastoma” AND “health utility” OR “glioblastoma” AND “health utilities” OR “glioblastoma” and “health preference” as the search terms.The search yielded a total of 77 publications. Only 3 publications turned out to be relevant in health economic context. All three publications use utilities for GBM derived from the same source (Garside et al.). Estimates of utility were therefore obtained from the NHS Value of Health Panel (VoHP) of which 36 members (out of 93) familiarized with the standard gamble method for preference elicitation, responded rating a total of 9 descriptive health state scenarios. This approach does not capture the presence or absence of AEs over time but assumes the constant presence of the AEs during the respective state.Additionally, Garside assumed a constant decline in QoL of patients in “progressive” state which may particularly not be adequate for long-term surviving patients experiencing a sustained stable disease after initial progression.The published health economic evaluations for GBM treatments rely on health utilities as determined by Garside et al through the standard gamble method in 36 healthy panel members of the UK National Health System. There are no published utilities for GBM in a general population sample. There are no reports that adequately adjust the utili…