Ensuring the quality of quality of life data: the Southwest Oncology Group experience.

The Southwest Oncology Group (SWOG) has successfully included quality of life (QOL) questionnaires in selected oncology treatment trials. Extensive quality control procedures have been necessary for obtaining and maintaining good questionnaire submission rates. Since the first QOL study was activated in SWOG in 1990, the Group has found it increasingly necessary to incorporate centralized monitoring of the QOL assessment schedule. Successful quality control strategies are presented. Current submission rates for five SWOG phase III treatment trials (both open and closed) and one chemoprevention trial are presented for those scheduled QOL assessments for which we have follow-up data. Reasons for missing QOL questionnaires and the extent of missing data within submitted QOL questionnaires are described for two different disease contexts: a trial for patients with advanced stage disease, and a trial for patients with earlier stage disease.