EORTC at the forefront of quality of life research at ISOQOL 2026

As one of the pioneers of health-related quality of life (HRQoL) research, it was only to be expected that EORTC, through its Quality of Life Group (QLG), would be well-represented at this year’s International Society for Quality of Life Research (ISOQOL) conference, held in Prague, Czech Republic, from 18-21 October. The theme of the conference was ‘Educate, Evaluate, Regulate’ and a number of EORTC presentations emphasised various aspects of this theme. Now that the value of patient-reported outcomes (PROs) is fully recognised, these presentations concentrated on tackling the issues around variations in their interpretation, and filling in gaps in their use.

With survival rates in paediatric oncology now exceeding 80%, focus has shifted from survival to HRQoL. But many existing PROs assessing quality of life did not sufficiently involve children’s self-report during questionnaire development and might therefore not adequately capture the child’s experiences.

Chiara Vetrano presented two new EORTC paediatric HRQOL assessment projects that aim to fill this gap; one for children aged eight to 14 and one for those under eight. The eight to 14 PRO assessments were developed through systematic reviews, which identified 129 issues. These were followed up with interviews with 47 children with cancer, with 45 parents, and with 22 healthcare providers across six countries. The findings were then discussed by experts (HRQOL experts, researchers, paediatric oncology clinicians and patient representatives), which resulted in a preliminary questionnaire consisting of one core scale, 38 items for clinical trials and practice, and an additional psychosocial scale of 12 items. The eight to 14-year-old test questionnaire provides a content-valid, child-informed instrument and is now ready for psychometric testing, the researchers say.

In parallel, the researchers are conducting a complementary approach for younger children under eight years. In this group, the systematic review identified four main domains (physical, psychological, social, and general) with several subdomains, and recruitment for interviews has begun. Taken together, these projects will establish the foundation for continuous PRO assessment from early childhood through adolescence.

While these questionnaires are intended to be used as stand-alone questionnaires, aligning their items and content to the EORTC QLQ-C30 is important to enable a lifelong measurement trajectory of patients’ HRQOL.

Furthermore, when assessing HRQOL in clinical trials, it is essential to include the children’s voices through the assessment of PROs. Whilst including PROs in clinical trials is recommended by regulatory agencies, children are still often under-represented and instead parents’ and caregivers’ proxy or observer assessments of the child’s HRQOL are used.

In this context, Chiara Vetrano also presented an ongoing project that aims to address the discrepancies between children’s self-reports and caregiver reports and the factors influencing this (dis-)agreement.

To better understand these differences, the researchers conducted a systematic review and meta-analysis examining the agreement between children’s self-reported HRQOL and proxy or observer reports in paediatric oncology. The review screened more than 3,500 studies and identified 145 for data extraction. Preliminary findings suggest that agreement tends to be higher for physical aspects of HRQOL than for psychosocial domains, is generally stronger for older children, and is higher between children and parents or caregivers than between children and healthcare professionals. This work is the first step in a broader EORTC QLG initiative to develop consensus-based recommendations on the optimal use of PROs and caregiver-reported outcomes in paediatric oncology trials.

Patient-reported outcomes are important in the understanding of health-related quality of life. But when they are not fully completed and data are missing, this may compromise the validity of trial findings. Dr Andreia Moura presented a study that aimed to uncover the reason behind non-completion in order to try to improve the situation.

The researchers conducted 31 semi-structured interviews with participants representing principal investigators, site nurses, trial sponsor representatives, patient representatives, study protocol writers, and electronic clinical outcome assessment (eCOA) providers. Analysis of the data revealed three levels of barriers – at that of the instrument, the patient, and the site. Challenges included redundant questionnaires, deterioration in patients’ health, overburdened staff and a lack of perceived relevance of PROs, the latter particularly among site staff. Interviewees reported site-level training on the value of patient-reported outcome measure (PROM) collection as an important factor in the improvement of completion rates. Patents identified that non-financial incentives (for example, feedback on how PROs are used) as well as flexibility and adaptation to patients’ needs could support completion.

Improving PROM completion rates in clinical trials requires a multifaceted approach targeting barriers at the instrument, patient, and particularly at site level. Training on the importance and impact of PRO data for site staff and patients, alongside flexible, patient-centred solutions, may enhance completion. These findings highlight the need for coordinated strategies that integrate methodological, educational, and operational solutions to strengthen the quality and completeness of PROMs in clinical trials.

If concise conclusions are to be drawn from PRO data in oncology practice and research, their interpretation needs to be standardised. Dr Monika Sztankay presented the new EORTC Quality of Life Group evidence-based guidelines to standardise the interpretation of scores from EORTC PRO measures.

The researchers carried out a systematic literature review to assess interpretation practices in 145 randomised controlled trials in breast, prostate, lung, bladder, gynaecological, and colorectal cancers that took place between 2016–2022. In parallel, 127 stakeholders (researchers, clinicians, industry, and patients) completed the online survey. Both approaches revealed substantial heterogeneity in the interpretation of EORTC PRO scores, particularly regarding definitions and thresholds for clinically meaningful change. An expert panel of 30 multidisciplinary experts prioritised 54 issues, and the resulting guideline provides consensus-based recommendations on EORTC interpretation thresholds, reference values, and norm data developed by the respective experts of the Quality of Life Group. Additional tools were co-developed with patients and clinical experts to support routine use.

The new EORTC PRO Interpretation Guideline addresses current heterogeneity in PRO interpretation by providing the first comprehensive, consensus-based framework for EORTC PRO measures, integrating existing evidence, expert consensus, and patient input. It is designed to enhance PRO evaluation, clinician education, and regulatory alignment for more consistent and clinically meaningful use of EORTC PRO data in oncology research and practice. The guideline and accompanying resources to support implementation across user groups is now freely available on the EORTC Quality of Life Group website.

Cancer survivors make up another group for whom health-related quality of life plays a significant role in their wellbeing, and this is increasingly important as their numbers grow. But existing questionnaires are not well adapted to the needs of this group, being limited in both content and generalisability.

Dr Lonneke van de Poll presented the EORTC QLQ-SURV100, a questionnaire to assess HRQoL in disease-free survivors of diverse cancers. It was tested by a total of 1480 participants from 46 centres in 21 countries. They had had breast, colorectal, prostate and other cancers, and were one to ten years post-treatment with no evidence of active disease. Rigorous evaluation showed consistency in answers derived from retests and that pre-defined hypotheses relating to sensitivity to treatment type, comorbidity, age, sex, and education level remained valid.

The researchers concluded that the EORTC QLQ-SURV100 is psychometrically robust and internationally applicable for assessing HRQoL in diverse cancer survivor populations, and that it captures a broad range of survivors’ experiences in physical, mental, and social domains. The questionnaire is suitable for use in clinical research, long-term follow-up, survivorship care planning, and evaluation of interventions and care models, they say, and this supports its potential to become a global standard for survivorship HRQoL assessment.

Pleural malignant mesothelioma is a rare, aggressive cancer that starts as a growth of cells in the mesothelium, specifically in the pleura. Prognosis is poor, making HRQoL a critical endpoint alongside survival. The use of PROs in mesothelioma trials has increased over the past decade, but to date no systematic overview on how HRQoL is defined, measured, and reported in these studies existed.

Dr Lotte van der Weijst presented results from a systematic review of interventional clinical trials published between January 2005 and December 2025 that included patients with pleural malignant mesothelioma and reported HRQoL outcomes using PRO measures. Thirty-four clinical trials met the eligibility criteria, spanning phase II–III interventional studies across chemotherapy, radiotherapy, surgery, targeted therapy, immunotherapy, and palliative care. Across the 34 studies, PRO measurement was heterogeneous, with assessment timing varying widely and many studies lacking clearly-defined PRO endpoints or missing follow-up completion rates.

The researchers conclude that HRQoL assessment in mesothelioma trials is methodologically inconsistent, limiting cross-trial comparability and interpretability of PRO findings. Future trials should adopt standardised PRO frameworks, including harmonised PROM selection, predefined PRO endpoints, complete reporting of response rates, and adherence to the Setting International Standards in Analysing Patient Reported Outcomes and Quality of Life Endpoints (SISAQOL) recommendations.

Other EORTC presentations included:

• Anne Esser: Quality of life endpoints in EORTC clinical trials: a descriptive protocol review (2010-2026)
• Alexandra Gilbert: Development and validation of the EORTC-PRO-AE inventory: An international mixed-methods study to establish face and content validity
• Niclas Hubel: How much is too much? Acceptable PROM response burden in chronic conditions: A scoping review
• Niclas Hubel: Time-dynamic versus time-static prediction models for impaired health-related quality of life in breast cancer – A methodological comparison using international harmonized data from the EORTC BALANCE database
• Tamara Jones: Single-item measures of treatment-related side effect burden in cancer: a synthesis of current guidance and evidence
• Andreia Moura: Face and content validity of a single item global indicator of cancer treatment burden: Evidence from cognitive interviews
• Morten Petersen: Psychometric evaluation of summary scores for the EORTC CAT Core
• Claudia Seidl: Stakeholder Perspectives on Assessment Modes of PROMs in Cancer Clinical Trials: A qualitative Study
• Monika Sztankay: The European Organisation for Research and Treatment of Cancer e-learning course on the use of patient-reported outcome measures in clinical practice
• Lisa Wintner: Development of an EORTC Health-Related Quality of Life Questionnaire for Renal Cell Cancer Patients: Phases 1-2

View the complete table of EORTC abstracts and sessions presented at ISOQOL 2026 here.

Caroline Hance (EORTC QLG Communications)
caroline.hance@eortc.org