Quality assurance of the EORTC Trial 22881/10882: boost versus no boost in breast conserving therapy. An overview

BACKGROUND: The initial quality assurance programme of the EORTC Radiotherapy Cooperative Group in trial 22881/10882 is described. The implications of its results for quality assurance in future trials are discussed. METHODS: In the EORTC trial 22881/10882 patients with stage I or II breast cancer are treated with tumor excision, axillary dissection, 50 Gy whole breast irradiation and then randomized to receive a boost dose of 15 Gy or no boost following complete tumor excision or between 10 Gy or 25 Gy in case of incomplete excision. To avoid or diminish protocol deviations and to quantify inevitable variations an extensive initial quality assurance programme was conducted. The programme consisted of a dummy run procedure an individual case review procedure, in vivo dosimetry studies and phantom dosimetry studies. RESULTS: This combination of quality assurance procedures allows a good estimation of patient to patient and inter-institutional variations, and early detection of (potential) systematic protocol deviations of 3 types: 1. Deviations due to ambiguities in the protocol prescriptions. 2. Deviations not known to the institution, such as mistakes in implementation of treatment planning algorithms resulting in a systematic overdosage or underdosage. 3. Inability of an institution to cope with (precise) protocol prescriptions for technical or logistic reasons. DISCUSSION: The first 2 types of deviations may be corrected or avoided by direct discussions and recommendations. With respect to the third type it is up to the trial coordinator to accept participation or not, depending upon the relative importance of the particular deviation(s) for the trial end points. To be effective, such a quality assurance programme must be implemented as early as possible in the course of a clinical trial