Investigating the equivalence of the EORTC QLQ-C30 and the QLQ-F17 (Equivalence C30/F17)

Regulatory bodies advocate for the measurement of well-defined function and symptom assessment tailored to each trial in order to minimize patient burden and to enhance the interpretability of the study results within the given clinical context. In addition to the common symptoms of cancer patients, the EORTC Core Questionnaire (QLQ-C30) includes six clearly distinguishable functioning scales that have been thoroughly tested and validated on an international level and that are available in 110 different language versions. The EORTC QLG has been responsive to the pragmatic request of regulators and users and has prepared a shortened version of the QLQ-C30 that is composed solely of items related to functioning. This so-called QLQ-F17 includes the Physical (PF), Role (RF), Emotional (EF), Cognitive (CF) and Social Functioning (SF) scales as well as the Global Health Status/Quality of Life (QL) scale in their original wording. The F17 has been endorsed by the EORTC QLG in September 2018. 

This useful questionnaire can be amended by symptom-specific symptom items taken from the item library [1]. This allows for a flexible, economic testing strategy, thus fitting the demands of regulators, users, and the overall strategy of the EORTC QLG. In a very recent draft guidance, FDA reiterated the request for short measures, referring to Q168 from the item library as an example of a single item scale to address patients’ therapy-related symptom burden [2]. 

It is an open question, however, whether the F17 is equivalent to the C30 in terms of measurement properties. Based on empirical research on response biases and order effects [3], it can be argued that the elimination of symptoms between RF and CF – Dyspnea (DY), Pain (PA), Fatigue (FA), Insomnia (SL), Appetite (AP), Nausea/Vomiting (NV), Constipation (CO), and Diarrhea (DI) – and of the Financial difficulties (FI) item between SF and QL could alter the manner in which subsequent items are completed. 

Thus, from a methodological standpoint, it is essential to confirm the psychometric properties of the F17 and to present evidence that scale values derived from the F17 are equivalent to those of the C30. The present project is designed to address this research question. 

Registered at clinicaltrials.gov (NCT05479682)

Trial setup finished

Regular Advisory Board meetings

Data sampling completed

Statistical Analysis Plan finalized

Analyses completed

Main publication prepared for submission

Preparation of further publications (Q1 2025) 

EORTC Core Questionnaire (QLQ-C30) is composed of questions relating to somatic symptoms (e.g. pain) or functioning (e.g. physical abilities) and is widely used in cancer clinical studies. A shortened version of this questionnaire contains only the 17 functioning items and is therefore call F17. The purpose of this project is to investigate whether the two questionnaires possess equivalent measurement properties and arrive at the same score values.