Quality assurance of the 22961 EORTC trial. A phase III study of the optimal combination of hormonal adjuvant treatment by LHRH analogue and radiation therapy for the management of locally advanced prostate cancer: the dummy run.

PURPOSE: The EORTC trial 22961, opened in 1997, was designed to investigate the optimal combination of hormonal adjuvant treatment by LHRH analogue and radiation therapy for the management of locally advanced prostate cancer. A dummy run was established to assess centre compliance to the radiotherapy protocol. MATERIALS AND METHODS: Medical and anatomical data obtained from 37 CT slices (5mm thickness) of an eligible patient were sent to 19 participating centres, which were asked to complete a questionnaire according to their practice and plan a theoretical radiotherapy treatment. The Planning Target Volume 1 (PTV1) should include prostate, seminal vesicles, internal iliac lymph nodes and inferior part of common iliac lymph nodes (extended pelvic fields). Centres which usually irradiate with small pelvic fields (N0 patients), were allowed to include the prostate, seminal vesicles and internal iliac lymph nodes plus a safety margin of 2 cm. For the Planning Target Volume 2 (PTV2), a safety margin of 1.5 to 2 cm should be around the prostate and seminal vesicles. Checks included patient positioning, treatment simulation, target volume definition, treatment set-up and clinical controls during treatment. RESULTS: Eleven institutions with actual 81% of patients' accrual in the protocol have responded. All centres used a supine treatment position and positioning lasers for the set-up, while 73 and 45% of the centres performed cystograms and used rectal contrast, respectively. Among the participating centres, 45% and 55% used blocks and MLC, respectively, to treat patients. Extended pelvic fields in terms of PTV1 were used by 63% of the centres. The remaining centres treated a small PTV1 with a 10-20 mm margin around to CTV1. All centres defined PTV2 according to protocol guidelines. Doses to PTV1 and PTV2 were correctly prescribed. It was difficult to assess the treated volumes due to a lack of standardisation in DVH calculations. CONCLUSION: In general, centres participating in the dummy run adhered to the guidelines. The dummy run enhances the reliability of the conclusions of the trial.

Quality assurance of the EORTC trial 22911. A phase III study of post-operative external radiotherapy in pathological stage T3N0 prostatic carcinoma: the dummy run.

INTRODUCTION: A dry run of a clinical trial (EORTC 22911) is presented in which 12 centres have participated. These are the centres which have contributed the largest number of patients to the trial. MATERIAL AND METHODS: Each participating centre received data from a suitable patient. Investigators were asked to plan and 'treat' the patient according to the protocol guidelines and return the data for evaluation of compliance. RESULTS: The results show that compliance to the protocol guidelines was generally good. There were a few minor deviations in the dose and fractionation schedule, in the volume reduction for the booster dose and in the dose prescription point. None of these deviations will affect the outcome of the study. The most important observation is the large inter-centre variation in target volumes. CONCLUSIONS: The results of this study underlines the need for a strict definition of the target volume and the adoption of the ICRU 50 recommendations in future protocols.