Quality-of-life assessment in cancer clinical trials: an intervention by itself?

Feasibility issues of quality-of-life (QL) assessment in cancer clinical trials have been discussed mainly in regard to compliance with QL questionnaires. In the case of an acceptable compliance, it is usually taken for granted that questionnaires received at the office for central data management have been filled in according to the rules and guidelines stated in the study protocol. The question whether local conditions of data collection might have a substantial influence on patients' QL estimation is not considered. In clinical experience, QL assessment in cancer patients may be a supportive intervention by itself, increasing awareness to QL issues in both patients and staff. To elaborate further on this question and the potentially interfering effects on patients' self-estimation we asked the nurses involved in the QL assessment of a randomized trial in small-cell lung cancer to describe their experiences. Meetings between the nurses collecting the data and the study coordinator took place on a regular basis. The detailed protocols of these meetings are used to describe qualitatively the possible influence of such unsystematically assessed factors on compliance and data quality. Implications regarding QL methodology are discussed.