Radiation Therapy (RT) Quality Assurance (QA) Analysis of Alliance A021501: Preoperative mFOLFIRINOX or mFOLFIRINOX plus Hypofractionated Radiation Therapy for Borderline Resectable Adenocarcinoma of the Pancreas (PDAC)

Abstract

<h3>Purpose/Objective(s)</h3> Alliance A021501 is the first national clinical trial to test the efficacy of stereotactic body radiation therapy (SBRT) in patients with PDAC. Herein, we aim to (1) review metrics used to provide high quality RT; (2) assess reasons for protocol deviations; and (3) analyze potential inter-observer variability with respect to contouring. <h3>Materials/Methods</h3> Each site was required to undergo credentialing prior to RT through IROC Houston. A tutorial for RT contouring and planning was recommended. Patients received SBRT (6.6 Gyx5) (strongly preferred) or hypofractionated RT (5 Gyx5) (HIGRT). Compliance criteria was provided for the target volume coverage and organs-at-risk (OARs). All cases required pre-treatment review by an experienced radiation oncologist (RO, TJ). Fiducials and daily imaging were required. Unacceptable deviations from the protocol were resubmitted for review and revised until approved. Cases requiring revision were carefully analyzed. RT plans were independently graded by 3 ROs with respect to several QA parameters. <h3>Results</h3> 40 patients were registered to receive RT (1 case planned but not treated) at 27 centers by 34 ROs. 16 centers were academic, 9 community. Centers were credentialed for an average of 3 years prior to enrollment (range: 0-9). 11 centers (6 academic, 5 community) required at least 2 attempts to pass credentialing. 23 centers were approved for moving lung/liver targets and 4 for static head and neck only. 33 patients were treated with SBRT, 6 with HIGRT. 5 cases (13%) required revision prior to RT. 54% patients (n=21) were female with a median age of 67 years. Time from enrollment to the start of RT was on average 117 days. Target and OAR volume data is shown in the Table. Motion management involved abdominal compression (33%), free breathing with increased margin (23%), or gating (23%). A median of 3 fiducials per case were used (range: 1-5). Details related to on-treatment delivery and image guidance were not recorded. Any deviations related to contouring or RT plans will be correlated with toxicity and outcomes. <h3>Conclusion</h3> There were no major deviations in RT planning. Variations in contouring, image fusion, and the potential influence of dose/fractionation differences on outcomes will be presented at the meeting. The results of this study serve to inform subsequent PDAC SBRT trial design and QA requirements.