Validation and scoring of the EORTC CAT measures

Since the 1990s physician ratings of a patients health status in clinical trials have been increasingly supplemented by ratings made by the patient her/himself, i.e. patient-reported outcomes (PROs). To assess PROs in cancer patients (in particular quality of life (QOL) as one of the major concepts within PRO research) a number of valid and reliable instruments has been developed (e.g. the EORTC QLQ-C30, the FACT-G, PROMIS measures, or the PRO-CTCAE). Traditional PRO measures, such as the widely used FACT-G and the EORTC QLQ-C30 use the same set of questions for all patients which has several disadvantages related to patient burden and measurement precision. To overcome these computer-adaptive measures based on Item Response Theory have been introduced to PRO assessment. Computer-adaptive PRO assessment is a sophisticated method for the assessment of PROs using individually tailored sets of questions to increase measurement precision and reduce the number of questions administered to each patient. CAT requires an item bank (i.e. a set of questions and their psychometric characteristics) and an algorithm for tailoring individual sets of questions. The EORTC Quality of Life Group has recently developed item banks for the computer-adaptive testing (CAT) of the domains covered by their widely used quality of life questionnaire, the EORTC QLQ-C30. These are called the EORTC CAT measures. Objectives This project will adress the following aims: A) Investigation of discriminatory, convergent and divergent validity of the EORTC CAT measures B) Investigation of sensitivity to change of the EORTC CAT measures C) Development of a scoring method (T-scores) for the EORTC CAT measures based on Austrian general population data Patients and Methods For investigation of discriminatory, convergent and divergent validity (aim A) we will recruit two samples of 300 mixed cancer patients (600 in total) and assess them with the 14 EORTC CAT measures and five further commonly used PRO measures covering related domains and collect clinical patient characteristics for known-group comparisons. Due to the high total number of questions, the assessment has to be split and administered to two different samples. For determination of sensitivity to change (aim B) we will recruit a sample of 280 breast and lung cancer patients at the start of chemotherapy (with anthracycline-based or platinum-based chemotherapy regimens) and assess them throught the course of chemotherapy. Sensitivity to change will be also investigated by assessing change in 240 prostate cancer patients receiving radiotherapy. For the development of a T-scores for the EORTC CAT measures (aim C) we will collect norm data in two representative samples of Austrian general population (n=2000 per sample, n=4000 in total). Since we administer the full item bank for each dimension to the subjects (about 250 items in total across 14 dimensions) it is again necessary to split the assessment in two parts and collect two samples.

The project "Validation and Scoring of EORTC CAT Instruments", funded by the FWF, dealt with the evaluation of the computer-adaptive quality of life questionnaires of the European Organisation for Research and Treatment of Cancer (EORTC). The EORTC is one of the world`s most important research groups in the development and evaluation of new cancer therapies, which also has a special focus on research into the quality of life of cancer patients. In our study of 604 cancer patients at the Medical University of Innsbruck and 1002 participants from the Austrian general population, it was shown that the newly developed, computer-adaptive EORTC quality of life questionnaires are high-quality instruments for the flexible recording of physical and psychosocial stress caused by cancer and its treatment. The computer-adaptive questionnaires, with their questions individually tailored to the patient, enable, for example, the assessment of physical, emotional and social function and the recording of important symptoms and treatment side effects such as fatigue (exhaustion), pain, loss of appetite, sleep disorders, shortness of breath and gastrointestinal symptoms. In our study, the computer-adaptive questionnaires were superior to conventional questionnaires (in which all patients answer the same questions) in terms of measurement accuracy and the ability to distinguish patients with symptoms of varying severity. In the context of clinical research, greater measurement accuracy enables studies to be conducted with smaller samples, which can shorten the duration of the study on the one hand, and reduce the costs of a study on the other. For the individual patient, a higher measurement accuracy means a lower patient burden due to the survey, since the relevant health areas can be recorded sufficiently precisely with fewer questions, i.e. shorter questionnaires. The standard data for the computer-adaptive EORTC questionnaires, which were created on the basis of 1002 participants from the Austrian general population, make it easier to interpret the results of the questionnaires, as it is easier to assess the severity at which a symptom or impairment deviates from "normal" values. Overall, the project contributed to the investigation of the measurement accuracy of quality of life questionnaires and thus contributes to their dissemination in clinical research, but also in daily practice. The importance of the patient perspective on disease and treatment can be further strengthened by using these questionnaires. The project is thus part of a general development in medical research that focuses on the patient in his entirety and individuality.