ESTRO 2020 Abstract book

S735 ESTRO 2020

classified in high risk and low risk when CIED distance from target was ≤10 cm and > 10 cm, respectively. CIED functioning was evaluated during and at the end of RT

of the prediction model was 0,86 (0,8 – 0,92, 95% confidence interval) (figure 1).

course. Results

10/48 patients were treated with tomotherapy. Total dose ranged from 8 Gy to 78 Gy. 32/48 patients had PM, 16/48 ICD. In 17 cases CIED distance from the target was ≤10 cm and in 31/48 distance was >10 cm. 15/31 and 4/31 low risk patients belonged to the first and the second group, respectively. Among these patients (both dependent and independent), 13 were treated with 6 MV photons, the remaining 6 patients were treated with > 6 MV. 12/31 low- risk patients were ICD wearers: 10 were treated with 6 MV photons, 2 with > 6 MV photons. 13/17 high-risk patients had PM (dependent or independent), among these, 11 were treated with 6 MV photon and 2 patients with > 6 MV. 4/17 high-risk patients were ICD carriers: 3 patients were treated with 6M photons while 1 pt with > 6 MV. During or at the end of RT course, 38/48 patients showed no cardiac rhythm disturbances, 3/48 had atrial fibrillation and 7/48 cases had ventricular events with no major clinical effects. After a mean follow-up of 19 months (range 2-41), 12 patients were evaluable for late assessment of CIED functioning and no ventricular event was observed. Conclusion The introduction of a protocol for the management of patients with CIED allows a standardization of the cardiological evaluation in RT workflow. In our experience, RT seems to be safe for CIED wearers. A larger number of patients will be required to confirm these preliminary results. PO-1303 Radiotherapy platform trials: accelerating our ability to answer important scientific questions A. Gilbert 1 , D. Sebag-Montefiore 1 , J. Brown 2 , S. Brown 2 1 Leeds Clinical Trials Unit- University of Leeds, Clinical Oncology, Leeds, United Kingdom ; 2 Leeds Clinical Trials Unit- University of Leeds, University of Leeds, Leeds, United Kingdom Purpose or Objective There is an increasing opportunity to test the benefit of dose alteration using IMRT and intensify treatment by combining novel agents with radiotherapy. Such studies are small, commonly non-randomised with wide variation in their design and delivery particularly in the phase Ib/II setting. Platform trials for individual disease settings are increasingly used in the evaluation of systemic therapies. We share our experience of radiotherapy platform trials. Material and Methods We describe platform trial methodology with reference to three interventional radiotherapy platform trial examples and highlight the benefits and limitations of this approach. Platform trials are conducted in a single disease, using a common control arm and commonly employ randomisation. They may include a pre-defined adaptive element enabling novel interventional arms to be added or ineffective ones to be dropped from the trial, sometimes using a multi arm multistage (MAMS) design. Results 1. PLATO (ISRCTN88455282 recruiting): Personalising anal cancer radiotherapy dose. This platform trial consists of 3 anal cancer trials (ACT) across the loco-regional disease spectrum. The interventions are stratified by tumour stage and treatment/dose is modified according to risk. ACT3 - non-randomised Ph2 study for excised T1N0 anal margin tumours with selective post-operative chemoradiotherapy. ACT4: Ph2 RCT CRT dose de-escalation (41.4Gy vs 50.4Gy in 28F) in T1-2N0 <4cm; ACT5: Pilot/Ph2/Ph3: RCT CRT dose escalation (53.2Gy vs 58.8Gy vs 61.1Gy) T3/4Nany and N+. Primary outcome: 3yr locoregional failure.

Conclusion A model was developed that predicts whether innovation implementation project in radiotherapy will be successful. If the critical and manageable factors of this prediction model are not secured in the project management of innovation implementation the chance of failure or delay are huge. The next step will be to validate this model in an external radiotherapy centre. This prediction model is the first of its kind and could be widely applicable to innovate more successfully in radiotherapy. PO-1302 Management and safety report for patients with cardiac implantable electronic device in radiotherapy S. Di Biase 1 , F. Fenu 1 , C. Di Carlo 1 , S. Costantini 1 , F. Cucciarelli 1 , M. Montisci 1 , M. Madia 1 , L. Vicenzi 1 , M. Giacometti 2 , M. Valenti 2 , M. Parisotto 2 , S. Maggi 2 , G. Mantello 1 1 Ospedali riuniti Ancona, Radiotherapy, Ancona, Italy ; 2 Ospedali riuniti Ancona, Medical Physics, Ancona, Italy Purpose or Objective Radiotherapy (RT) can influence cardiac implantable electronic devices (CIED) functioning. Several consensus documents and guidelines have been published but data on this issue are still limited. We report our institutional protocol for the management of patients with PM or ICD undergone RT and our results in terms of CIED malfunctioning. Material and Methods 48 consecutive CIED patients admitted to our Institution were evaluated. A cardiologist with expertise in arithmology evaluated at baseline patients that were stratified into three classes. The first group included PM wearers and spontaneous activity; the second one, patients with PM but without any residual spontaneous activity; the third group included patients with ICD. For the first two groups, the cardiologist of reference indicated to set the PM in asynchronous mode during RT delivery and evaluated patients after every RT fraction. For the third group, the cardiologist disabled and enabled ICD before and after every RT section, monitoring cardiac activity during the treatment delivery. Patients were