ESTRO 2024 - Abstract Book

S2956

Interdiscplinary - Other

ESTRO 2024

Hospital, Medical Physics, Norwich, United Kingdom. 12 The Christie Hospital, Christie Medical Physics and Engineering, Manchester, United Kingdom. 13 Haukeland University Hospital, Department of Oncology and Medical Physics, Bergen, Norway. 14 McGill University Health Center, Department of Medical Physics, Montreal, Canada. 15 St Luke's Radiation Oncology Network, Medical Physics, Dublin, Ireland. 16 Brainlab AG, Munich, Munich, Germany. 17 NHS Wales´s Singleton Hospital Radiotherapy Centre, Medical Physics, Swansea, United Kingdom. 18 MemoriaI Sloan Kettering Cancer Center, Department of Medical Physics, New York, United Kingdom. 19 Department of Radiation Oncology, University of Michigan, Ann Arbor, USA. 20 Leeds Institute of Medical Research at St James’s, University of Leeds, Leeds, United Kingdom. 21 Department of Radiation Oncology, Physics unit, Lyon, France

Purpose/Objective:

Reirradiation is a complex treatment option requiring a dedicated workflow to guarantee patient safety. The Clinical Workflow group of the ESTRO Physics Working Group on Reirradiation aimed to identify critical steps within the reirradiation workflow to aid in future work that will create a consensus-based best practice guidelines for safe reirradiation management.

Material/Methods:

A modified Delphi technique is being used to develop best practice guidelines. An international expert group, consisting of 25 European and North American participants (20 clinical physicists, 3 industry physicists, 1 physician, and 1 dosimetrist) has been engaged in the process since December 2022. Participants have met regularly via video conference to discuss current practices and workflow challenges, and to define statements for voting rounds. Practice patterns and institutional experiences were collected in an initial survey prepared by members of the Clinical Workflow group.

Results:

Twelve institutions responded to the initial survey. There was substantial variability in workflow and personnel involved in identifying patients who have received prior irradiation and how patient medical records were collected. Treatment planning and evaluation of accumulated dose workflows were more closely aligned among the survey respondents; staffing generally included physicians, physicists, and dosimetrists/planners; and the composite dose was most often evaluated in radiobilogically equivalent dose EQD2 (using either a custom calculation, such as an Excel table, or TPS-supported programmes for converting physical dose to EQD2). Except for four centres, rigid registration was exclusively used for dose accumulation (8/12). For half of the institutions (6/12), a second independent check of dose summation was performed by a physicist, at least for the EQD2 calculations. Overall, the majority of centres reported a lack of comprehensive guidelines specific to the reirradiation context (8/12) and highlighted the need for formalization and standardization of the process. The expert group identified seven major steps in the reirradiation workflow from the survey and resulting discussion which would benefit from reirradiation-specific guidance: (1) timely identification of reirradiation referrals, (2) data collection, (3) information provided for simulation information, (4) prescription definition, (5) information for planning, (6) dose accumulation and approval, and (7) QA and information for treatment (Fig.1). There is an on-going dialogue regarding what information needs to be considered during the reirradiation process, who should be involved, how data should be shared with relevant stakeholders, and how information from previous treatment and current treatment should be recorded in the patient record. To improve treatment safety and efficiency, statements are being developed related to multidisciplinary communication processes,