ESTRO 38 Abstract book

S643 ESTRO 38

cataracts or other late toxicity was found. Figure 1

(43%). Table. 1 represents the clinical aim to radiologic imaging revision. Cases’ stratification according to radiologic indication is represented in Fig. 1 . Follow-up showed that radiology-driven MDT decision was correct in 117 of the 118 cases with available follow-up (99%), with 43 patients having a histological confirmation. Conclusion Data emerging from our work strongly support the inclusion an expert radiologist in the core of each institutional HN MDT. Further efforts of prospective nature are warranted in order to assess whether imaging revision translates into improved oncological outcomes in this clinical setting. EP-1161 Clinical response and toxicity of VMAT low- dose RT with intravenous steroids for Graves’ Orbitopathy B. Salas 1 , R. Cabrera 1 , L. Ferrera 1 , M. Lloret 1 , M. Zajac 1 , J. Rutllan 2 , F. Medina-Rivero 2 , P.C. Lara 3 1 Hospital Universitario de Gran Canaria Doctor Negrín., Radiation Oncology, Las Palmas de Gran Canaria, Spain ; 2 Hospital Universitario de Gran Canaria Doctor Negrín., Ophthalmology, Las Palmas de Gran Canaria, Spain ; 3 Hospital Universitario San Roque/Universidad Fernando Pessoa Canarias, Oncology, Las Palmas de Gran Canaria, Spain Purpose or Objective Radiotherapy has been considered an alternative to high doses glucocorticoids in progressing GO. Low doses (LD- RT) produce an anti-inflammatory effect and seemed to be equally effective than the old common fractionation protocol of 20 Gy, in 10 daily doses over a two-week period. Lower doses of 10 Gy fractionated in 1 Gy a week over 10 consecutive weeks, have been not studied under the new techniques as volumetric modulated arc therapy (VMAT) or Intensity-modulated radiation therapy (IMRT). Furthermore, there is no publications about the efficacy ant toxicity of the combined use of LD-RT VMAT/IMRT and high doses glucocorticoids. The aim of this study is to analyze for the first time the clinical response and toxicity of a LD-RT VMAT/IMRT schedule plus high doses glucocorticoids in moderate to severe GO. Material and Methods 33 patients (59 orbits) with diagnosis of moderated to severe Graves’ ophthalmopathy (GO) according to EUGOGO were included in this prospective cohort study under our RT Quality Assurance programmed from March 2013 to February 2018. Treatment schedule consisted in retro-orbital LD-RT with VMAT or IMRT (Total Dose 10Gy. 1Gy/fraction/week) and concurrent high dose intravenous glucocorticoids therapy (Methylprednisolone 6 doses of 500mg/week, followed by 4 doses of 250 mg/week). The treatment response was evaluated by clinical activity score (CAS: Range 0-7), considering active GO CAS ≥ 3 and inactive GO CAS <3. Toxicity was scored by the CTC4.0 criteria. Clinical evaluation was jointly done by the ophthalmologist and the radiation oncologist at 3 months intervals. Follow-up was closed in October 1, 2018. Results All patients completed the irradiation and concurrent steroids therapy schedule. 29 orbits (49.2%) had active GO symptom score (CAS ≥ 3) before treatment and a mean pretreatment-CAS of 4,1. Three months after treatment all 59 orbits (100%) had inactive GO symptom score (CAS < 3). A marked reduction from mean pretreatment-CAS of 4,1 to posttreatment-CAS of 1,6 was observed (p=0.003) (Figure 1). During follow-up 1 patient (1 orbit) required posterior decompression surgery, and 3 patients (4 orbits) required strabismus surgery due to reactivation and progression of GO symptoms. Three-year freedom from surgery was 81.5+/-9.5% (Figure 2). Acute toxicity was very mild (only grade I): eye dryness: 18 orbits (30,5%) eye redness in 9 orbits (15,25%), and photophobia 1 orbit (1.69%). Toxicity from glucocorticoids therapy was G0. No

Figure 2

Conclusion Highly-conformation techniques (VMAT/IMRT) retro- orbital LD-RT (10Gy, 1Gy/fraction/week) and concurrent high dose intravenous glucocorticoids is a very active treatment for Moderate to Severe Graves´ Orbitopathy. Acute toxicity was very low and no cataracts appeared in the follow-up period Rescuing surgery was needed in very few cases with a 3-year freedom from surgery of 81.5+/- 9.5%. EP-1162 Post-radiotherapy sarcopenia: a new prognostic factor in oropharyngeal cancers? C. Dupin 1 , R. Poncin 1 , A. Daste 2 , C. Majoufre 3 , V. Castetbon 3 , E. De-Mones 3 , R. Trouette 1 , V. Vendrely 1 1 Bordeaux University Hospital, Radiation Oncology, Bordeaux, France ; 2 Bordeaux University Hospital, Medical Oncology, Bordeaux, France ; 3 Bordeaux University Hospital, Head Neck Surgery, Bordeaux, France Purpose or Objective Sarcopenia, or loss of muscle mass, is common in oncology, and is associated with survival in some retrospective studies. The objective of this study was to evaluate pre- and post-radiotherapy (RT) sarcopenia in patients treated for oropharyngeal cancer and its impact on survival. Material and Methods All consecutive patients treated for oropharyngeal cancer by irradiation without surgery with curative intent at