ESTRO 2020 Abstract book

S32 ESTRO 2020

Purpose or Objective On February first 2019, the Multi-OutcoMe EvaluatioN of radiation Therapy Using the MR-linac study (MOMENTUM) opened for accrual. MOMENTUM is a prospective, international registry which facilitates technical development, clinical evaluation and evidence-based implementation of MRI guided Radiotherapy using the Unity MR-linac (Elekta AB). The MR-linac integrates a linear accelerator with a 1.5T diagnostic quality MRI and an online adaptive workflow. Here we present our 9-month experience of the MOMENTUM study. Material and Methods MOMENTUM study is an international academic-industrial- partnership between seven hospitals and industry partner Elekta (Elekta AB, Stockholm, Sweden). After initiation of the study, all patients treated with the MR-linac were eligible for inclusion. Pseudonymized clinical and technical patient data are captured at set time intervals until 24 months after treatment with the MR-linac. Clinical data, stored in an Openclinica database, include demographics, tumor characteristics, treatment details, toxicity, disease recurrence and survival data. Technical data, i.e. all the data generated and used by the machine before, during and after treatment is stored on a cloud-based platform. All participants in MOMENTUM provide informed consent for use of their data by the academic consortium partners and for data sharing with the industry partner except for Dutch patients. In The Netherlands patients can choose whether they want to share their data with the industry partner. Furthermore, all participants are asked to provide additional consent for collection of patient reported outcomes (PRO) and additional MRI scans on the MR- linac. Results Between February and October 2019, the study opened in all seven institutes, and until now, 200 patients have provided informed consent for participation in MOMENTUM. At time of writing, we accrued 127 patients with known information on tumor location with a median age of 66 years. 71% (n=90) of 127 patients were male. Most patients were treated for oligometastases (N=42), rectal cancer (N=21), or prostate cancer (N=12) (Figure 1). 95 patients had complete treatment data with a mean number of fraction per patients of four to 33. For 199 participants, preferences regarding additional data collection and data sharing with the industry were known. 197 (99%) of 199 participants shared data with industry partner Elekta, 80% (N=159) of participants consented to additional research MRIs, and 67% (N=133) of participants chose to collect additional PROs (Figure 2).

Conclusion The MOMENTUM study, an international multi-institutional registry, opened successfully at several sites and accrued 200 patients treated with the Unity MR-linac. Participants were treated with a mean number of fraction of four to 33 per patient. MOMENTUM contributes to optimal collection and usage of data of patients enabling the evidence-based implementation of the MR-linac. PD-0072 Evaluation of intra thoracic anatomical changes based on the lung traffic light protocol F. Rodrigues Sousa 1 , Y. Jourani 2 , S. Poeta 2 , L. Moretti 1 , M. Roelandts 1 , P. Van Houtte 1 , M. Somoano 1 , D. Van Gestel 1 1 Institut Jules Bordet ULB, Radiotherapy, Brussels, Belgium ; 2 Institut Jules Bordet ULB, Medical Physics, Brussels, Belgium Purpose or Objective Treating lung cancer patients can be challenging. During the course of radiotherapy, intra-thoracic anatomical changes (ITACs) such as tumor regression, tumor displacement/deformation, pleural effusion, and/or atelectasis can result in a deviation from the intended planned treatment. In order to more easily manage these variations according to their potential impact, a Traffic Light Protocol (TLP) has been applied as a clinical decision support system. The current study analyzes the impact of ITACs on lung treatments either for primary lung tumor or for lung metastases, and whether the criteria used were adequate and clinically useful for selecting patients requiring plan adaptation. Material and Methods Cone beam CT scans from 75 patients (84 lesions) treated with VMAT between November 2018 and July 2019 were analyzed, including 50 SBRT treatments and 34 non-SBRT treatments. Figure 1 represents the type of treatment delivered for each tumor stage. The TLP (Table 1) was adapted from Hattu et al. and was implemented by means of an in-house program which was developed through collaboration between physicians, physicists and RTTs. Our TLP used the following criteria: possible tumour progression, tumour regression, baseline shift, pleural effusion, atelectasis, and pneumonia. For these criteria, frequency and follow-up action (i.e. no action required, new CT or plan adaptation) were scored.