Radiotherapy quality assurance for the PEACE 1 trial: An individual case review analysis

Abstract

Purpose: Radiotherapy quality assurance (RTQA) is essential for ensuring adherence to trial protocols. This paper summarizes the individual case review (ICR) results from the PEACE-1 trial, a phase-III study investigates standard of care (androgen deprivation therapy with or without docetaxel) with or without local radiotherapy; and with or without abiraterone acetate plus prednisone in patients with metastatic hormone-sensitive prostate cancer (mHSPC).

Materials and methods: Participating institutions submitted radiotherapy (RT) plans for central review, assessing protocol compliance in target volume and organs at risk (OARs) delineation, as well as dose specifications. ICRs were conducted either retrospectively (r-ICRs), after starting RT, or prospectively (p-ICRs), before RT initiation. Case reviews were categorized as acceptable per protocol, acceptable variation, or unacceptable variation based on delineation and dose and plan parameters.

Results: Out of 585 patients in the RT arms, 527 (90%) had r-ICRs, primarily using intensity-modulated radiotherapy (IMRT). Delineation review approved 417 (87%) r-ICRs and 44 (92%) p-ICRs. The main reasons for unacceptable delineation were erroneous clinical target volume (CTV) delineation. In dose and plan reviews, 399 (96%) r-ICRs cases and 46 (96%) p-ICRs were approved, with unacceptable cases primarily due to PTV dose distribution issues.

Conclusion: RTQA is crucial in prostate cancer trials, primarily for proper target volume delineation. It is recommended to omit r-ICRs due to resource demands and lack of impact on RTQA outcomes, using limited p-ICRs with early feedback for site deviations and reserving full p-ICRs for trails with new techniques or dose regimens.

Clinicaltrials: gov: NCT01957436.

Keywords: PEACE-1; Prostate cancer; Quality assurance; RTQA.