Radiotherapy quality assurance for the RTOG 0834/EORTC 26053-22054/NCIC CTG CEC.1/CATNON intergroup trial "concurrent and adjuvant temozolomide chemotherapy in newly diagnosed non-1p/19q deleted anaplastic glioma": Individual case review analysis.

BACKGROUND The EORTC phase III 26053-22054/ RTOG 0834/NCIC CTG CEC.1/CATNON intergroup trial was designed to evaluate the impact on concurrent and adjuvant temozolomide chemotherapy in newly diagnosed non-1p/19q deleted anaplastic gliomas. The primary endpoint was overall survival. We report the results of retrospective individual case reviews (ICRs) for the first patient randomized per institution to detect the compliance with the study protocol. MATERIAL AND METHODS Sixty-nine institutions were required to submit the radiotherapy plan of their first randomized patient. Full digital datasets uploaded to the EORTC server were assessed by three independent and blinded reviewers through the EORTC radiotherapy quality assurance platform. RESULTS Sixty-two (90%) of sixty-nine ICRs were received and assessable. Of the 62 cases, 22 were evaluated as per protocol (35.5%), 11 as acceptable variation (17.7%) and 29 were classified as unacceptable variations (46.8%). Most common unacceptable variations were related to the PTV dose (n = 19, 31%) and delineation (n = 17, 27%) processes. CONCLUSIONS The ICR analysis showed a significant number of unacceptable variations with potential impact on tumor control and/or toxicity profile. Prospective ICRs are encouraged for future studies to prevent and correct protocol violations before start of treatment.