ESTRO 2024 - Abstract Book

S2913

Interdiscplinary - Other

ESTRO 2024

1 University of Notre Dame Australia, School of Medicine, Fremantle, Australia. 2 GenesisCare, St Vincent's Hospital, Sydney, Australia. 3 UNSW Sydney, School of Clinical Medicine, Sydney, Australia. 4 GenesisCare, Murdoch, Perth, Australia. 5 Fiona Stanley Hospital, Department of Radiation Oncology, Murdoch, Australia

Purpose/Objective:

Peer review by a multidisciplinary team is an important component of quality assurance in radiotherapy (1) and has been advocated by multiple professional organizations (ie. ASTRO and RANZCR) to ensure patient safety and plan quality in Radiation Oncology (2, 3). Magnetic resonance (MR) guided radiotherapy (MRgRT) is an emerging treatment delivered from an MR linear accelerator (MR-Linac) that allows for real-time adaptive image guidance with superior soft tissue visualisation and treatment precision. To our knowledge, there are currently no studies reporting on the feasibility and outcomes of the peer review process for MRgRT on the MR-Linac despite the planning complexity involved and evolving clinical indications suitable for this technology.

This study evaluated the role of peer review in the planning process for MRgRT with the aim of quantifying the rate of change in the treatment plans and the amount of time and resources required for the peer review process.

Material/Methods:

We prospectively collected cases presented at weekly MR-Linac peer review meetings across two centres from 8 June to 21 September 2023. All cases that are considered to be complex (ie. stereotactic body radiotherapy (SBRT), retreatment, or rare cases as determined by the radiation oncologists) must be presented at the peer review meeting before initial treatment. Attendees include radiation oncologists, radiation therapists and medical physicists, and clinical fellows. Cases were analysed to determine the rate and extent of plan changes after case presentation and evaluated based on the Peer Review Audit Tool for Radiation Oncology (PRAT) developed by the Royal Australian and New Zealand College of Radiologists (RANZCR) (4) . Technical and clinical aspects of each patient’s treatment were evaluated simultaneously pursuant to the PRAT.

Results:

All cases (n=55) presented were adult patients. The majority of cases (76.4%, n=42) had oligometastatic /oligoprogressive disease. Common treatment sites were the liver (32.7%, n=18) followed by lymph nodes (29.1%, n=16), pancreas (12.7%, n=7), adrenal (10.9%, n=6) and prostate (10.9%, n=6). The majority of the cases were treated with SBRT (83.6%, n=46). A total of 30.9% (n=17) of cases were retreatment cases, having had prior radiotherapy at/near the treatment site. We observed that 36.4% (n=20) of cases had changes made to their treatment plans after the peer review meeting, with 3.6% (n=2) having major changes involving the decision to defer radiotherapy, while the remaining minor changes resulted in treatment re-planning. The most frequent treatment change was to organs at risk volumes (16.4%), followed by total dose and fractionation (10.9%) and target volume dose coverage (5.5%). Higher rates of treatment plan change were observed in patients with SBRT plans (39.1% cf 22.2% of non-SBRT plans), oligometastatic/oligoprogressive sites (38.1% cf 30.7% in non-oligometastatic/oligoprogressive plans) and retreatment (41.2% cf 34.2% in non-retreatment cases). Overall, each case took a mean of 7 minutes (range 2-15 minutes) to discuss.

Conclusion: