ESTRO 2021 Abstract Book

S1237

ESTRO 2021

association was detected in male patients (0.43 (0.14 - 1.28), p=0.12). However, in female patients (N=75), high YB-1 mRNA levels were significantly associated with poorer overall survival (5.38 (1.57 - 18.44), p=0.002). Conclusion This study highlights that analysis of YB-1 mRNA levels according to sex can affect both the strength and the direction of associations with overall outcome. Further evaluation of the relevance of these findings to specific response to radiotherapy are warranted. PO-1510 Electrochemotherapy as a radiosensitizer in preclinical and clinical settings: a systematic review. M. Ferioli 1,2 , A.M. Perrone 3 , M. Buwenge 1,2 , A. Arcelli 1,2 , A. Zamagni 1,2 , G. Macchia 4 , F. Deodato 4,5 , S. Cilla 6 , L. Tagliaferri 7 , F. De Terlizzi 8 , P. De Iaco 3,9 , C. Zamagni 10 , A.G. Morganti 1,2 1 Radiation Oncology, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy; 2 Department of Experimental, Diagnostic and Specialty Medicine – DIMES, Alma Mater Studiorum Bologna University, Bologna, Italy; 3 Division of Oncologic Gynaecology, IRCSS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy; 4 Radiation Oncology Unit, Gemelli Molise Hospital – Università Cattolica del Sacro Cuore, Campobasso, Italy; 5 Istituto di Radiologia, Università Cattolica del Sacro Cuore, Roma, Italy; 6 Medical Physic Unit, Gemelli Molise Hospital – Università Cattolica del Sacro Cuore, Campobasso, Italy; 7 Fondazione Policlinico Universitario "A. Gemelli" IRCCS, UOC di Radioterapia Oncologica, Dipartimento di Diagnostica per Immagini, Radioterapia Oncologica ed Ematologia, Rome, Italy; 8 Scientific & Medical Department , IGEA S.p.A. , Carpi (Mo), Italy; 9 Oncologic Gynaecology Unit, Department Medical and Surgical Sciences (DIMEC), University of Bologna, Bologna, Italy; 10 Oncologia Medica Addarii , IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy Purpose or Objective Electrochemotherapy (ECT) is a local treatment combining electroporation (EP) and chemotherapeutic agents. ECT can overcome the chemo- or radio-resistance acquired by tumor cells after multiple local and systemic treatments. Moreover, both ECT and irradiation (IR) could activate the immune system towards neoplastic cells. The aim of this review is to evaluate the potential role of EP and ECT as radiosensitizers. Materials and Methods In vitro and in vivo studies reporting on ECT or EP combined with IR were included in this systematic review. Studies not reporting tumor response or radiosensitivity parameters were excluded. The search was based on Medline, Scopus, and The Cochrane Library databases. Results The literature search, after removing of duplicates, led to the identification of 713 papers. Eleven studies (preclinical data in 10 studies and one clinical study) were included in the final analysis. Tumors were treated with EP alone and with ECT in two and nine studies, respectively. IR was delivered only with a single fraction in 10 studies, while hypofractionated treatment in one to five fractions was reported in one study. Despite the heterogeneity in reporting treatment response and the different subgroups analyzed in each study, ECT achieved improved tumor response when associated with IR compared to any single therapy or treatments combination. In fact, in vitro studies showed that EP significantly enhances the tumor control rates obtained with IR alone. Moreover, both higher IR total dose and dose per fraction improve the results of EP-IR combination. All preclinical and clinical in vivo studies showed a synergistic effect of ECT and IR as compared to single treatments and to other combinations of them, in terms of tumor growth delay and of IR dose required to achieve tumor control, regardless of tumor histology. Conclusion Based on this analysis, the combination of ECT and IR seems to improve local tumor control suggesting a radio- sensitizing effect of ECT. The mechanisms underlying this interaction and the possible role in the clinical setting deserve further studies. PO-1511 50 years of radiotherapy research: evolution, trends and lessons for the future T. Berger 1 , D.J. Noble 2 , L.E. Shelley 1 , K.I. Hopkins 3 , D.B. McLaren 2 , N.G. Burnet 4 , W.H. Nailon 1,5 1 Edinburgh Cancer Centre, Western General Hospital, Department of Oncology Physics, Edinburgh, United Kingdom; 2 Edinburgh Cancer Centre, Western General Hospital, Department of Clinical Oncology, Edinburgh, United Kingdom; 3 International Atomic Energy Agency, ,, Vienna, Austria; 4 The Christie NHS Foundation Trust, ,, Manchester, United Kingdom; 5 the University of Edinburgh, School of Engineering, , Edinburgh, United Kingdom Purpose or Objective Rapid and relentless technological development in an ever-more globalized world has shaped the field of Radiation Therapy (RT) in which we practise today. We hypothesised that a data-driven analysis of the literature from the last 50 years would improve our understanding of where we have come from, and where we are now, and hence provide insights on the future direction and requirements of the field. Materials and Methods The PubMed database was searched with the keywords cancer radiotherapy yearly from 1970 to 2019. This yielded 358,114 publications distributed over time as shown in Fig.1 and for which, the authors’ names and affiliations were collected and analysed. In particular, the evolution of the geographic distribution of research output was investigated from 1990 to 2019 and illustrated in Fig.2. Considering the 20 journals with the most significant research contribution, several metrics on publications per author were calculated. Furthermore, to understand the evolution of cancer therapies used in conjunction with RT, the proportion of publications returned with keywords pertaining to therapies detailed in Fig.1 was assessed.