ESTRO 2021 Abstract Book

S1217

ESTRO 2021

the spleen in radiotherapy in abdominal tumours is not considered and there are no defined dose limits. Our study performs a dosimetric and clinical assessment of splenic irradiation in a group of patients. Materials and Methods Between June 2018 and February 2020, eight patients were included, 4 patients treated with SBRT for abdominal tumours (2 patients with pancreas adenocarcinoma and 2 patients with lymph nodes) and 4 patients treated with chemoradiotherapy (CRT) (3 patients with pancreas adenocarcinoma and 1 patient with cholangiocarcinoma). After spleen delineation, spleen volume, maximum, minimum, mean, and V5 to V40 doses were calculated. Leukocytes, lymphocytes, neutrophils, platelets, haemoglobin, PCR and admissions for infections in the year following radiotherapy were analysed. Results The mean spleen volume was 295.31cc (69,44cc-731cc). Maximum doses were 9.06Gy and 33.81Gy (p=0.09), mean doses were 1.27Gy and 13.82Gy (p=0.05) and minimum doses were 0.24Gy and 6.48Gy (p<0.05) for the SBRT and CRT groups respectively. The mean V5, V10, V15 and V20 were 9.67cc and 317.08cc; 0.14cc and 263.77cc; 0.06cc and 307.19cc; 0 and 256.84cc in the SBRT and CRT group respectively. Mean leucocytes, lymphocytes, neutrophils, haemoglobin and platelets were 5776.67/mcl and 2530/mcl (p=0.089); 1183/mcl and 385/mcl (p=0.33); 3650/mcl and 1610/mcl (p=0.1); 11.66g/dl and 11.05g/dl (p=0.53); 211666.67/mcl and 114000/mcl (p=0.93) in the SBRT and CRT groups respectively at 6 months. Fifty percent of patients had recurrent infections leading to admissions in the CRT group and none in the SBRT group (p=0.1). Conclusion The doses received by the spleen in abdominal radiotherapy are not negligible. The potential effects of splenic irradiation are not known. More studies are needed to establish the need to consider the spleen as an OAR but it is possible that its importance is influenced by the era of immunotherapy. PO-1487 Brachytherapy training survey among Radiation Oncology residents in Europe A. Sturdza 1 , M. Stephanides 2 , J.G. Eriksen 3 , K. Benstead 4 , P. Hoskin 5 , S. Vlad 6 , A. Escande 7 , S. Corradini 8 , S. Konrad 9 , H. Westerveld 10 , L. Tagliaferri 11 , D. Najjari 12 , K. Konat-Bąska 13 , V. Plesinac Karapandzic 14 , L.T. Tan 15 , R. Nout 16 , B. Peters 10 , K. Tanderup 17 , I. Jürgenliemk-Schulz 18 , M. Kamrava 19 1 Medical University of Vienna, Comprehensive Cancer Center Vienna, Department of Radiation Oncology, Vienna, Austria; 2 Medical University of Vienna, Department of Statistics, Vienna, Austria; 3 Department of Oncology, Aarhus University Hospital, Denmark, Department of Experimental Clinical Oncology, Aarhus, Denmark; 4 Gloucestershire Oncology Centre, Cheltenham General Hospital, Department of Oncology, Gloucester, United Kingdom; 5 Mount Vernon Cancer Centre, Northwood, Hertfordshire, Department of Oncology, London, United Kingdom; 6 Neolife Enayati Medical City, Department of Radiation Oncology, Bucharest, Romania; 7 Centre Oscar Lambret, Department of Radiation Oncology, Lille, France; 8 University Hospital, LMU Munich, Department of Radiation Oncology, Munich, Germany; 9 Medical University of Vienna, Department of Radiation Oncology, Vienna, Austria; 10 Amsterdam University Medical Centers, AMC, Department of Radiation Oncology, Amsterdam, Netherlands Antilles; 11 Interventional Oncology Centre (IOC), Fondazione Policlinico Universitario A. Gemelli IRCCS, Dipartimento di Diagnostica per immagini, Radioterapia Oncologica ed Ematologia - Gemelli ART (Advanced Radiation Therapy), Rome, Italy; 12 Hospital Duran iReynals, Institut Catalàd'Oncologia (ICO), Radiobiology and Cancer Group, ONCOBELL Program, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Department of Radiation Oncology, Barcelona, Spain; 13 Wroclaw Comprehensive Cancer Center, Wroclaw Medical University, Department of Oncology, Wroclaw, Poland; 14 Institute for Oncology and Radiology of Serbia, Department of Radiotherapy, Belgrad, Serbia; 15 Cambridge University Hospitals NHS Trust, Department of Oncology, Cambridge, United Kingdom; 16 Erasmus MC, Department of Radiation Oncology, Rotterdam, Netherlands Antilles; 17 Aarhus University Hospital, Department of Oncology, Aarhus, Denmark; 18 University Medical Centre Utrecht, Department of Radiation Oncology, Utrecht, Netherlands Antilles; 19 Cedars Sinai Medical Center, Los Angeles, CA, Department of Radiation Oncology, Los Angeles, USA Purpose or Objective Brachytherapy (BT) is a well-established treatment technique that has been used for over 100 years in successfully treating a wide range of cancers. For patients to continue having access to this treatment, residents need to be adequately trained. We investigated the state of BT training in Europe to better understand barriers to residents feeling comfortable with practicing BT. Materials and Methods An online 22-question survey was created based on the survey by the American Association of Radiation Oncology Residents from 2017 with questions added that are unique to training in Europe. The survey addressed several BT topics, including site-specific training (prostate, gynecologic, breast, gastro-intestinal and skin), volume of experience, barriers to training, institutional support, and preferences for further training. Responses to individual statements were given on a 1 to 5 Likert-type scale, reflecting strength of opinion. The survey was sent to 1250 residents in two iterations (November 2019 and February 2020). The answers were divided by junior and senior years of training (< 4 versus ≥ 4 years of training). Descriptive statistics were used to describe frequencies. Results Residents from a total of 21 European countries participated and 445 responded to the survey (36%). Among them, 205 (47%) were seniors. The percentage of residents considering that performing BT independently at the end of residency was very or somewhat important was 66% among the juniors, and 49% for the seniors. Exposure to brachytherapy cases during the whole duration of training is variable amongst senior residents with 50% reporting doing > 5 vaginal cylinder cases for postoperative endometrial cancer, 37% > 5 intracavitary cervical cancer cases, and 23% > 5 gynecologic interstitial cases. Only 20% of senior residents reported performing > 5 prostate cases with 49% having performed none. Senior trainees reported the greatest barriers to achieving independence in BT to be lack of appropriate didactic/procedural training from the supervisors (47%), decreased case load (31%) and lack of personal interest (18%). About 68% of all respondents reported their program lacks a formal brachytherapy curriculum