Abstract Book

S909

ESTRO 37

quality of training, level of knowledge as well as their working conditions and professional satisfaction. Material and Methods From June 2016 to February 2017 a survey was conducted by the young DEGRO (yDEGRO) using an online platform. The questionnaire consisted of 28 items examining a broad range of aspects influencing residency. There were 96 completed questionnaires. Results 83% of participants stated to be very or mostly pleased with their residency training. Moderate working hours and a good colleagueship contribute to a comfortable working environment. Level of knowledge regarding the most common tumor sites (i.a. palliative indications, lung, head-and-neck, brain, breast, prostate) was pleasing. Radiochemotherapy embodies a cornerstone in training. Modern techniques such as intensity-modulated radiotherapy (IMRT) and stereotactic procedures are now in widespread use. Education for rare indications and center-based procedures offers room for improvement. Conclusion Radiation oncology remains an attractive and versatile specialty with favorable working conditions. Continuing surveys in future years will be a valuablemeasuring tool to set further priorities in order to preserve and improve quality of training. EP-1693 Utility of Magnetic Resonance imaging in the diagnosis of Radiation osteitis in sarcoma patients C. Carvajal 1 , J. Cacicedo 1 , F. Casquero 1 , B. Canteli 2 , A. Urresola 2 1 Hospital de Cruces, Radiation Oncology, Baracaldo- Vizcaya, Spain 2 Hospital de Cruces, Radiology, Baracaldo-Vizcaya, Spain Purpose or Objective To evaluate Magnetic Resonance (MR) imaging patterns of differentiation from osteitis to other induced bone changes or tumoral extension, after radiotherapy (RT) of soft tissue sarcomas (STS). Material and Methods Twenty- one patients were selected from March 2004 to December 2010, from our database of sarcomas at Cruces University Hospital, from March 2004 to December 2010. All of them, STS of extremities, who underwent radical surgical resection and radiotherapy. Image findings in MR were reviewed to differentiate potential post-treatment changes, from recurrent tumor. Results 51, 38% patients were female, and 47.62% male. 3 cases of radiation osteitis were identified (14.2%). The mean age was 65.6 years. Median dose was 55 Gy (range, 45–60 Gy). MR shows changes in the marrow signal within the region of tumor bed, these abnormalities have low intensity in T1 sequences and high signal in T2 and STIR. After administration of gadolinium, in T1 weighted and SPIR sequences, slight heterogenous enhanced areas appear, due to fibrotic changes. These signal changes are focal, show geographic distribution, a faint enhancement mainly in peripheral areas, are not accompanied by soft tissue mass, does not exist in the first MR controls, and they increase in size and number at subsequent follow- up. Conclusion MR can illustrate abnormal bone change distribution and is useful for diagnosing osteitis by characteristic intensity

patterns. Adding STIR sequence would be considered if radiation osteitis is suspected.

EP-1694 Radiotherapy for Ledderhose disease of the feet R. Shaffer 1 , C. Freeland 2 , I. Jeevarathnam 1 , L. Pardon 2 1 St. Luke's Cancer Centre Royal Surrey County Hosp, Clinical Oncology, Guildford, United Kingdom 2 Genesis Cancer Care- St Martha Oncology Centre, Radiotherapy, Guildford- Surrey, United Kingdom Purpose or Objective An audit was carried out to assess the effectiveness of radiotherapy for Ledderhose disease of the foot (plantar fibromatosis). This is a benign condition, closely associated with Dupuytren's disease of the hand, that can cause significant pain and functional impairment. Material and Methods Thirty-nine patients were treated with radiotherapy in two centres between 2011 and 2016. One centre used kilovoltage photons, and the other used electrons. Yearly questionnaires were sent, asking about treatment response and side-effects. Results Twenty-four patients returned at least one questionnaire. Their average age was 52 years (range 23 – 74 years), six male and 18 female, average follow-up 2.2 years (range 1-5). Indications for treatment (often multiple) were; pain in 19/24, reduced mobility in 8/24, large or growing nodules in 23/24. 16/24 had one foot treated, and 8/24 had both feet treated. 10 were treated using kilovoltage photons (140kV at 50cm SSD), 13 with 6MeV electrons with 0.5 cm bolus, and one with 6MV photons. The dose was 15Gy in 5 fractions over 1 week, with a 2-4 month gap, and then a further 15 Gy in 5 fractions, for a total dose of 30 Gy in 10 fractions. Side effects were seen in 6/24 (25%) patients; dry skin in 5/6 and pain in 1/6 patients. All were CTC grade 1. There were no reports of radiation-induced carcinoma. Patients described their feet as being overall improved in 19/24 (79%) cases at latest follow up, with improvement in functionality in 18/24 (75%), improvement in nodules in 20/24 (83%), and reduction of pain in 17/24 (71%). None reported worsening disease or symptoms. Conclusion Radiotherapy is an effective treatment for Ledderhose disease, and causes minimal side-effects. F. Deodato 1 , S. Cilla 2 , G. Macchia 1 , A. Ianiro 2 , A. Picardi 1 , M. Ferro 1 , G. Tolento 3 , G. Siepe 3 , M. Buwenge 3 , C.M. Donati 3 , L. Ronchi 3 , R. Vanini 4 , S. Cammelli 3 , G.P. Frezza 5 , V. Valentini 6 , A. Morganti 3 1 Fondazione di Ricerca e Cura “Giovanni Paolo II”, Radiotherapy Unit, Campobasso, Italy 2 Fondazione di Ricerca e Cura “Giovanni Paolo II”, Medical Physics Unit, Campobasso, Italy 3 Department of Experimental- Diagnostic and Specialty Medicine - DIMES- University of Bologna- S.Orsola- Malpighi Hospital, Radiation Oncology Unit, Bologna, Italy 4 Department of Experimental- Diagnostic and Specialty Medicine – DIMES- University of Bologna- S. Orsola- Malpighi Hospital, Medical Physics Unit, Bologna, Italy 5 Bellaria Hospital, Radiation Oncology Unit, Bologna, Italy 6 Policlinico Universitario «A. Gemelli»- Università EP-1695 VMAT radiosurgery boost after EBRT in oligometastatic patient with vertebral metastases