Radiotherapy quality assurance of the prospective randomised EORTC-1219/DAHANCA-29 trial: an individual case review analysis

Background: The EORTC-1219/DAHANCA-29 trial investigated whether adding nimorazole to accelerated radiotherapy (RT) and chemotherapy improves locoregional control of locally advanced head and neck cancer. As part of the trial's RT quality assurance (RTQA) program, individual case review (ICR) of RT plans was performed to assess protocol compliance and treatment planning quality. Materials and methods: Nineteen centers submitted RT plans for central review. The trial mandated prospective ICR (p-ICR) for the first five patients per institution, with subsequent plans reviewed retrospectively or as optional p-ICR. Plans were reviewed by radiation oncologists and medical physicists. Plans deemed unacceptable in p-ICR were resubmitted for review, whereas retrospective ICR (r-ICR) cases were reviewed once. Plans were categorized as “Acceptable as per protocol,” “Acceptable variation,” or “Unacceptable variation.”. Results: RT plans for all 194 randomized patients were reviewed, with 174p-ICRs and 44 r-ICRs. The delineation acceptability rate for p-ICR improved from 69% at the first submission to 93% at final review. p-ICR had an 18% higher acceptance rate (90%) compared to r-ICR (73%). Dose and plan acceptability remained high (97%) at both first and final submission, with minimal differences between p-ICR and r-ICR. Conclusion: P-ICR significantly improved CTV delineation quality, ensuring higher protocol compliance and treatment planning accuracy. p-ICRs are recommended for complex treatments, tailored to the performance of individual sites.