PRO140 Health-Related Quality of Life Associated with Mycosis Fungoides-Type Cutaneous T-Cell Lymphoma Patients: Determination of Utility Values from a UK-Based Clinician Questionnaire

Abstract

Utility studies quantify the impact of disease on patients’ health-related quality of life (HRQoL). In rare diseases particularly, utility data are often limited. Where direct elicitation of data from patients is unfeasible, indirect methods are required to determine health state utility values (HSUVs). Here, we present indirect elicitation of HSUVs for patients with mycosis fungoides (MF), a rare skin lymphoma characterised by painful, itchy skin patches and plaques, which can progress into tumours and may involve blood, lymph nodes and viscera. Twelve distinct vignettes were prepared, based on published literature and expert opinion. The vignettes were validated by a MF patient expert and described typical MF patients with varying disease stage (IA-IVB) and skin burden, as assessed by the modified Severity Weighted Assessment Tool (mSWAT). Other included patient characteristics (age, Eastern Cooperative Oncology Group [ECOG] score) were informed by a patient registry. UK clinicians, working at key NHS lymphoma treatment centres (N=7), acted as respondents and completed the EQ-5D-5L questionnaire (proxy version 2) electronically for each vignette, responding as they believed MF patients would. Responses were converted into HSUVs using the UK value set. In every disease stage, HSUVs decreased with increasing mSWAT score. Similarly, for each mSWAT range HSUVs decreased as disease stage advanced. This demonstrates the effect of increasing skin burden and disease progression on HRQoL. Despite this, HSUVs associated with mSWAT score=0 were similar, regardless of disease stage (0.945 in Stage IA, 0.924 in Stage IB-IIA and 0.917 in Stage IIB-IV). The results of this investigation suggest that proxy-reporting via EQ-5D represents a potential option for generating HRQoL data, if published estimates are not available. Despite the small sample size and indirect elicitation of data, the finding that HRQoL decreases with increased mSWAT score is aligned with published literature.