Evaluation of the psychometric properties of patient-reported outcome measures for the assessment of health-related quality of life across the European cancer continuum: a systematic review applying COSMIN methodology

Introduction The EUonQOL project aims at developing a new Patient-Reported Outcome Measure (PROM; i.e., EUonQOL-Toolkit) for Health-Related Quality of Life (HRQoL) assessment that will be applied across a wide variety of cancer patients and survivors across the European Union and its associated countries. To inform the development of this PROM, it is necessary to leverage on the current state of the field and to assess, following the highest methodological standards, the PROMs currently available to assess HRQoL in European cancer patients and survivors. The aim of this systematic review was to (1) identify all available PROMs for HRQoL assessment in European cancer patients and survivors, and (2) assess the psychometric properties of the identified PROMs. Methods and analysis This systematic review was performed following the PRISMA-P (Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocols) guidelines. The search was performed up to March 2024 to capture PROMs measuring HRQoL across the cancer continuum in both MEDLINE and ELSEVIER. The evaluation of the PROMs’ psychometric properties, data extraction and data synthesis were conducted according to the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) methodology. Results A total of 156 articles were included, reporting on 36 unique PROMs, which covered a wide range of HRQoL domains. Among those, a selection of the subscales of the EORTC Quality of Life Core Questionnaire (EORTC QLQ-C30), the Impact of Cancer (IOC) and the Integrated Palliative care Outcome Scale (IPOS) demonstrated sufficient content validity and at least low-quality evidence for sufficient structural validity and internal consistency. For all the other PROMs, sufficient evidence was lacking. None of the PROMs captured in this review could be assessed across all measurement properties due to insufficient evidence. Conclusion Overall, this systematic review highlights the need for more high-quality studies reporting on the measurement properties of the PROMs used to assess HRQoL in cancer patients and survivors across Europe. Across 36 identified instruments, a selection of subscales of only 3 PROMs, namely the EORTC QLQ-30, the IOC and the IPOS, met the recommendation criteria defined by the COSMIN guidelines. Protocol registration number CRD42023418616.