ESTRO 36 Abstract Book

S21 ESTRO 36 _______________________________________________________________________________________________

2 Ospedale Bellaria, Radiotherapy Department, Bologna, Italy 3 University of Bologna, Department of Medical and Surgical Sciences - DIMEC, Bologna, Italy 4 Rizzoli Institute, Department of Oncology, Bologna, Italy 5 Fondazione di Ricerca e Cura “Giovanni Paolo II”, Radiotherapy Unit, Campobasso, Italy 6 Fondazione di Ricerca e Cura “Giovanni Paolo II”, Medical Physics Unit, Campobasso, Italy Purpose or Objective Whole Lung Irradiation (WLI) represents a treatment option in patients with lung metastases from Ewing Sarcoma. However, prospective trials reporting impact of WLI on outcome and toxicity are few and discordant. Aim of our analysis was to systematically review the available literature to better define toxicity of WLI in patients with Ewing Sarcoma and Osteosarcoma. Secondary endpoints were overall survival (OS) and disease-free survival (DFS) analysis. Material and Methods A systematic review based on PRISMA methodology of papers reporting studies on prophylactic or curative bilateral WLI was performed using PubMed, Cochrane Library and Scopus. Combination with other treatment as chemotherapy and surgery was allowed. Only article published in English were considered. Results According to title and abstract 115 studies were screened and 12 of them met the inclusion criteria (4/12 were randomized controlled trials), reporting results on 649 patients. Clinical mild and moderate impairment as dyspnea and cough was reported in 49 patients (7.6%). Severe pneumonitis occurred in 13 patients (2.0%). Smoking significantly increased WLI toxicity and toxicity rates were higher in WLI combined with chemotherapy, surgery or radiotherapy boost. No impact of WLI on OS was WLI produce a relatively low rate of radiation-induced severe effects. However, a positive impact on patients outcome was not demonstrated. New strategies to prevent or treat lung metastases have to be tested in these patients. PV-0048 Prognostic impact of tumor size and response in neoadjuvant radiotherapy of soft tissue sarcoma A. Cortesi 1,2 , A. Arcelli 1,3 , R. Frakulli 1 , L. Giaccherini 1 , S. Bisello 1 , G. Bianchi 4 , D.M. Donati 4 , M. Gambarotti 5 , S. Ferrari 6 , A. Farioli 7 , R. Vanini 8 , G. Macchia 9 , F. Deodato 9 , S. Cilla 10 , V. Picardi 9 , G. Torre 9 , G. Ghigi 2 , A. Romeo 11 , G.P. Frezza 3 , A.G. Morganti 1 , S. Cammelli 1 1 University of Bologna, Radiation Oncology Unit- Department of Experimental Diagnostic and Speciality Medicine - DIMES, Bologna, Italy 2 Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori IRST- IRCCS, Radiotherapy Department, Ravenna, Italy 3 Ospedale Bellaria, Radiotherapy Department, Bologna, Italy 4 Istituto Ortopedico Rizzoli, III Clinica Ortopedica, Bologna, Italy 5 Istituto Ortopedico Rizzoli, Department of Pathology, Bologna, Italy 6 Istituto Ortopedico Rizzoli, Department of Oncology, Bologna, Italy 7 University of Bologna, Department of Medical and Surgical Sciences - DIMEC, Bologna, Italy 8 University of Bologna, Medical Physic Unit, Bologna, Italy 9 Fondazione di Ricerca e Cura "Giovanni Paolo II", Radiotherapy Unit, Campobasso, Italy 10 Fondazione di Ricerca e Cura "Giovanni Paolo II", Medical Physics Unit, Campobasso, Italy described. Conclusion

11 Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori IRST- IRCCS, Radiotherapy Department, Meldola, Italy Purpose or Objective To evaluate clinical-radiological response and outcome in patients with primary or recurrent soft tissue sarcomas (STS) of extremities treated with neoadjuvant chemoradiation. Material and Methods Sixty patients (median age 52 years, range: 23-87) with primary (54 patients, 90%) or recurrent (6 patients, 10%) STS, were treated with neoadjuvant chemotherapy (CHT) and pre-operative external beam radiotherapy (RT: 50 Gy in 25 daily fractions). Selection criteria were diseases of large dimension (> 5 cm) or in close proximity of critical structures such as nerves or vessels. The Gross Tumor Volume (GTV), defined as macroscopic disease visible in the T1-weighted sequences, was delineated based on MRI images. MRI images were merged with CT-simulation scans. For CTV definition we added a 4 cm margin in cranio-caudal direction and a 1 cm radial margin (except where anatomical barriers were present) to GTV. CTV to PTV margin was 1 cm added isotropically. All patients underwent CT scan and MRI of the interested anatomical region plus chest TC before and after RT (before surgery). For the aims of this analysis the tumor volume before and after RT was divided into quartiles. Results With a median FU of 58.5 months (range 12-116), only one patient had local relapse 24 months after surgery and was treated with surgical re-resection, with local control of the disease in the following radiological-clinical investigations. Fifteen patients (25%) developed metastases. Six out of 60 patients died (10%). Only 20 patients (33.3%) received postoperative RT-boost for marginal or intralesional margins. At preoperative MRI tumor volume showed an average reduction of 18% (range -90% to +191%). Patients with smaller tumors at diagnosis (volume < median) showed a trend for improved 5-year disease-free survival (DFS) (81.3% vs 64.3%; p=0.075). In patients with very large tumors at diagnosis (4th quartile), a significant volume reduction after RT was correlated with very high 5-year DFS (100%) and 5-year OS (100%). Patients presenting with smaller but volumetrically enlarged lesions showed worse 5-year DFS (50%) and 5- year OS (50%). Five-year DFS and OS of patients with volume of larger dimensions before and after RT (4th quartile) were 46.2% and 72.7%, respectively. Tumor reduction after neoadjuvant therapy was significantly correlated with DFS (p:0.002) and OS (p:0.027). Conclusion In this series of patients treated with preoperative RT a high LC rate was recorded. Pre-treatment and volumetric changes of tumor size significantly predicted patients outcome. Prospective studies on neoadjuvant setting of STS are necessary to improve outcome in high-risk groups. PV-0049 Recurrent skull base and extra-cranial chordoma following proton therapy: clinical outcomes. M. Kountouri 1 , M. Walser 1 , R. Schneider 1 , A. Bolsi 1 , A. Lomax 1 , D. Weber 1 1 Paul Scherrer Institute PSI, CPT, Villigen PSI, Switzerland Purpose or Objective The aim of this study was to evaluate the clinical outcomes in patients diagnosed with a recurrence of a skull base or extra-cranial chordoma following treatment with pencil beam scanning (PBS) proton radiation therapy. Material and Methods Between November 1997 and December 2015, 77 patients with a mean age of 51.3 years (range 22.3 – 79.6 years) were treated for a skull base (N=38) or extra-cranial (N=39) chordoma with PBS proton therapy and later presented with a recurrence. Of those patients treated for