ESTRO 36 Abstract Book

S729 ESTRO 36 2017 _______________________________________________________________________________________________

METHOD: From 2010 to 2016 we treated 17 pts, median age 78 years, with diagnosis of NMSC (5/17 basal cell carcinoma, 11/17 squamous cell carcinoma, 1/17 trichilemmal carcinoma ), ≥ 3cm (range 3-8 cm diameter), GTV median volume was 32cc (range 5-60 cc). Only 1 pt presented extremity disease (malleolar region) and the others had head region disease.Total dose was 36 Gy in 6 Gy/fractions twice a week. Pts were evaluated 1 month after the end of treatment and then every 3 months. At the follow up pts were assessed for acute and late toxicity according to the Radiation Therapy Oncology Group criteria and treatment response according to Recist criteria. Results Median follow up was 12 months.We reported CR in 9/17 pts (53 %), PR in 8/17 pts (47.%) at one month after the end of the treatment. No PD was observed. No pts had acute side effect that required treatment interruption. Acute toxicity was grade 1 RTOG in 3/17 pts. 1/17 had grade 2 RTOG late skin toxicity with moderate fibrosis and The Hypofractionated schedule of 36 Gy in 6 Gy/fractions 2/week in elderly pts gave good results in term of treatment response and of acute and late side effects even in lesions ≥3cm. The treatment was well tolerated in all cases and the shorter regime facilitates compliance of elderly pts reducing the number of Hospital visits. discromia. Conclusion EP-1375 Volumetric-modulated-arc-therapy versus 3D- conformal-radiotherapy for sarcoma of extremities A.M. Ascolese 1 , P. Navarria 1 , P. Mancosu 1 , S. Tomatis 1 , A. Fogliata 1 , P. Colombo 1 , R. De Sanctis 1 , A. Marrari 1 , D. Franceschini 1 , G.R. D'Agostino 1 , A. Santoro 1 , V. Quagliuolo 1 , M. Scorsetti 1 1 Istituto Clinico Humanitas, Radiotherapy and Radiosurgery, Rozzano Milan, Italy Purpose or Objective To assess the impact of volumetric-modulated arc therapy (VMAT) compared with 3D-conformal radiotherapy (3DCRT) in patients with newly diagnosed soft tissue sarcoma (STS) of the extremities in terms of toxicity, local control (LC) rate and patients overall survival (OS). Material and Methods The present retrospective study includes patients with newly diagnosed STS of extremities treated at our institution. All patients underwent limb-sparing surgery and adjuvant radiation therapy. 3DCRT was adopted between 2006-2010 and VMAT between 2011-2015. The median total dose prescribed was 66 Gy (range 60-70 Gy) in 33 fractions in both groups. The clinical target volume (CTV) corresponded to the surgical cavity and planning tumor volume (PTV) was generated adding and isotropic margin of 1 cm. All plans were optimized on PTV. Clinical outcome was evaluated by physical examination, contrast- enhanced MRI, thoracic and abdominal computed tomography (CT) scan two months after RT and then every 3 months. The tumor progression was described as local, if it occurred in primary site. Toxicity was evaluated with Common Terminology Criteria for Adverse Events (CTCAE) scale version 4.0. Results From January 2006 to December 2015, 147 patients were treated. The greater number of patients had liposarcoma and leiomyosarcoma histology (62%). Preoperative tumor volume was > 10 cm in maximum diameter in 62 (42%) of patients and ≤ 10 cm in 85 (58%). Radical surgery was performed in 85 (58%) patients and marginal or closed in 62 (42%). Preoperative or postoperative chemotherapy Electronic Poster: Clinical track: Sarcoma

was administered in 73 (49.6%) patients. The median follow up time was 45.04 months. The 5 years LC rate was 80.79% for the whole cohort, 73.98 for 3DCRT patients and 85.26% for VMAT, respectively. The 5 years OS rate was 68.85% for the entire cohort, 61.1% for 3DCRT group and 80.64% for VMAT, respectively. All but one dosimetric parameters were in favor of VMAT. In detail, PTV V95% was higher for VMAT; bones volume receiving 50 Gy was significant lower for VMAT (p<0.05). For the lower extremities, the maximum dose (i.e. 1cm 3 ) to the contra- lateral leg was smaller for the 3D approach (median: 16Gy vs 7.2Gy). Acute soft tissue G3 toxicity was observed in 10 patients underwent 3DCRT and in 2 received VMAT. G1 fibrosis was recorded in 80% of patients while osteomyelitis conditioning pain and bone fractures in 2 patients in 3DCRT group. Factors conditioning LC and OS, on univariate and multivariate analysis was the tumor size (p<0.01) and the surgical radicality (p<0.01). Conclusion the availability of modern RT technique permit a better conformity on the target with maximum sparing of normal tissue and lower side effects. This matter is hopefull for prospective study using moderate hypofractionated RT schedule. EP-1376 IOERT combined with EBRT in R1-resected soft tissue sarcomas of the extremities: a pooled analysis F. Roeder 1,2 , A. De Paoli 3 , I. Alldinger 4 , G. Bertola 5 , G. Boz 3 , J. Garcia-Sabrido 6 , M. Uhl 7 , A. Alvarez 8 , B. Lehner 9 , F. Calvo 8 , R. Krempien 10 1 LMU Munich, Department of Radiation Oncology, Munich, Germany 2 German Cancer Research Center DKFZ, Department of Molecular Radiation Oncology, Heidelberg, Germany 3 Centro di Riferimento Oncologico, Department of Radiation Oncology, Aviano, Italy 4 University of Heidelberg, Department of Surgery, Heidelberg, Germany 5 Centro di Riferimento Oncologico, Department of Surgery, Aviano, Italy 6 University Hospital Gregorio Maranon, Department of Surgery, Madrid, Spain 7 University of Heidelberg, Department of Radiation Oncology, Heidelberg, Germany 8 University Hospital Gregorio Maranon, Department of Radiation Oncology, Madrid, Spain 9 University of Heidelberg, Department of Orthopedics, Heidelberg, Germany 10 Helios Clinic, Department of Radiation Oncology, Berlin, Germany Purpose or Objective To report the results of a European pooled analysis evaluating the use of IOERT combined with EBRT in R1- resected patients with extremity STS. Material and Methods Three European expert centers participated in the current analysis. Only patients with R1-resection of an extremity STS who received IOERT and EBRT were included. Patient with gross incomplete resections, primary lesions outside the extremities, nodal or distant metastasis prior/at IOERT or missing EBRT documentation were excluded, leaving 68 patients for the analysis. Median age was 59 years and median tumor size 8 cm. 68% of the patients presented in primary situation with 72% of the tumors located in the lower limb. Stage at presentation (UICC 7 th ) was I:12%, II:49%, III:40%. Most patients showed high grade lesions (FNCLCC grade 1:12%, 2:34%, 3:54%, predominantly liposarcoma (38%) and MFH (28%). IOERT was applied to the tumor bed with a median dose of 12.25 Gy using a median electron energy of 8 MeV. IOERT was preceeded (16%) or followed (84%) by EBRT with a median dose of 46 Gy in all patients. 22% of the patients received additional chemotherapy. Results