3670 - Enhancing Radiotherapy Quality Assurance in Lymphoma: A Rigorous Real-Time Central Review Process
Presenter(s)
A. C. Lo1, S. A. Milgrom2, R. Mailhot Vega3, D. Hodgson4, H. Chapman5, S. Kessel5, S. Flampouri6, S. Y. Cho7, H. Schoder8, J. Mhlanga9, N. Pandit-Taskar10, H. Laie11, C. Gowdy12, J. Qi13, N. Abu Ata14, B. Hu15, F. Keller16, S. Castellino16, K. M. Kelly17, and B. S. Hoppe18; 1Division of Radiation Oncology, Department of Surgery, University of British Columbia, Vancouver, BC, Canada, 2University of Colorado, Department of Radiation Oncology, Aurora, CO, 3UF Health Proton Therapy Institute, Jacksonville, FL, 4Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada, 5Imaging and Radiation Oncology Core, Lincoln, RI, 6Emory School of Medicine, Atlanta, GA, 7University of Wisconson-Madison, Madison, BC, Canada, 8Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, 9Washington University School of Medicine, Department of Radiology, Division of Nuclear Medicine, St. Louis, MO, 10Memorial Sloan Kettering Cancer Center, New York, NY, 11Children's Hospital of Orange County, Orange County, CA, 12BC Children's Hospital, Vancouver, BC, Canada, 13Medical College of Wisconsin, Milwaukee, WI, 14Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 15University of Utah Huntsman Cancer Institute, Salt Lake City, UT, 16Children Hospital of Atlanta, Atlanta, GA, 17Roswell Park Cancer Institute, Buffalo, NY, 18Mayo Clinic, Jacksonville, FL
Purpose/Objective(s): Radiation therapy quality assurance (RTQA) is crucial in clinical trials to ensure protocol-compliant treatment, which improves disease control, reduces toxicity and ensures trial outcomes’ interpretability. As radiotherapy (RT) for lymphoma has evolved, increasing complexity necessitates a rigorous RTQA process. Here we describe our early experiences in centrally reviewing RT in the NCTN AHOD2131 study (NCT05675410) for early-stage classic Hodgkin lymphoma.
Materials/Methods: AHOD2131 employs an interim PET-response adapted strategy for treatment randomization in which an estimated 15% of the study cohort (N=267 pts) will receive RT. Our central review process for the study incorporates a structured, multi-step process designed to ensure accurate target volume delineation, appropriate dose coverage, and adherence to organ-at-risk (OAR) constraints. The process involves institutional submission of simulation CT, PET/CTs, and contours to the Imaging and Radiation Oncology Core Group Rhode Island (IROC-RI). Nuclear medicine radiologists perform an initial review of PET/CTs, identifying sites of disease involvement and assigning Deauville scores on interim and end-of-systemic therapy scans. Subsequently, the radiation oncology central review team, composed of IROC-RI staff and multiple radiation oncologists (ROs), promptly conducts a virtual review. This review process ensures that PET/CTs are accurately registered with simulation CT, target volumes are appropriately delineated, and OAR doses comply with protocol-defined constraints. Feedback is provided to treating ROs, who must address any required revisions before final approval and treatment initiation.
Results: Early implementation of this rigorous RTQA process has been successful in identifying potential protocol deviations and providing timely feedback within 1-2 business days. Common errors include suboptimal PET/CT fusion leading to inaccurate contouring, omission of sites of initial disease involvement from ISRT volumes, and contouring that unnecessarily includes uninvolved OARs. Errors related to PET/CT fusion are often related to differences in body positioning between PET/CT and simulation CT scans, necessitating multiple registrations or “mental fusion” for accurate delineation. Additionally, misinterpretation of pre-treatment imaging contributes to target volume errors, underscoring the importance of careful review of baseline imaging.
Conclusion: A standardized, rigorous RTQA process is essential for modern lymphoma trials to ensure maintenance of smaller radiation volumes that reduce toxicity but minimize the risk of geographic misses in early-stage HL. The real-time central review methodology implemented in AHOD2131 is the most comprehensive RTQA approach in lymphoma trials to our knowledge. Its successful early implementation highlights the importance of structured RTQA in optimizing treatment delivery, serving as a model for future clinical trials.