ESTRO 2021 Abstract Book

S51

ESTRO 2021

Fig. 1 CONSORT (Consolidated Standards of Reporting Trials) diagram of patients with CSM, treated at our department between 2003 and 2017

Fig. 2 Kaplan-Meier plots of progression-free survival (PFS) for all patients with CSM treated with surgery only (A), combined modality of surgery and FSRT (B), and FSRT only (C). Five-year PFS rates were 55.7%, 100.0% and 100.0% for A, B, and C respectively. Ten-year PFS rates were 19.2% and 100.0% for A and B, and not yet reached for group C. B and C improved PFS significantly (p<0.001) compared to A. Conclusion Personalized treatment strategies for CSM patients are essential to control space-occupying or functionally compromising lesions. The additional potential side effect of radiotherapy seems to be justified under the aspect of longer tumor control with low functional risk. In the absence of space-occupying effect, a sole radiotherapeutic concept is reasonably possible.

Proffered papers: Proffered Papers 5: Applied dosimetry

OC-0079 EPID in vivo dosimetry implementation world-wide: results of an ESTRO survey M. Esposito 1 , J.B. van de Kamer 2 , E. Bossuyt 3 , S.F. Kry 4 , D. Verellen 5 , C. Clark 6 , N. Jornet Sala 7 1 Azienda Sanitaria USL Toscana Centro, S.C. Fisica Sanitaria Firenze-Empoli, Firenze, Italy; 2 The Netherland Cancer Institute, Division of Radiotherapy, Amsterdam, The Netherlands; 3 Iridium Netwerk, Radiation Oncology , Antwerp, Belgium; 4 M.D. Anderson Cancer Center, Radiation Physics, Houston, USA; 5 Iridium Netwerk, Radiation Oncology, Antwerp, Belgium; 6 University College Hospital London, Radiotherapy, London, United Kingdom; 7 Hostpital de la Santa Creu i Sant Pau, Radiation Physics, Barcelona, Spain Purpose or Objective In vivo dosimetry (IVD) is known to be an effective quality assurance method to detect deviations between prescribed and administrated dose. From the available IVD systems, the Electronic portal imaging device (EPID) has been shown to have great potential for large scale acquisitions of in vivo dosimetry (IVD) data. In recent years, many institutes developed EPID IVD programs with commercial or homemade software. In this work we investigated the critical aspects and the effectiveness of the IVD implementation with a focus on EPID based IVD on an international level. Materials and Methods An ESTRO working group, created a survey containing 44 questions [Fig1] divided in three parts: IVD software characteristics, software implementation and data analysis, and patients results. The survey was sent to the ESTRO mailing list on 14 October 2019 and was closed on 30 November 2019.