ESTRO 37 Abstract book

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ESTRO 37

Results From February 2007 to February 2017 a total of 35 patients with 58 lesions were included in our analysis. Leiomyosarcoma (41%) and synovial sarcoma (27%) were the most represented histologies. Five patients (15%) were identified with LM at the diagnosis. For the remaining 30 patients, LM appeared with a median time of 51 months (range 6-311 months). Median follow-up time from initial diagnosis was 87 months (5-251 months) and from SBRT was 31 months (2-92 months). Grade I–II late toxicity was recorded in 19 (54%) patients and it was diagnosed on CT scan at 9 and 12 months. No severe toxicity (grades III-IV) was observed both in acute and late setting. No patients required hospitalization. The actuarial 5-years local control rate (from SBRT treatment) was 96%. Overall survival at 2- and 5-years was 70% and 63.8%, respectively. At last follow-up 22 patients (62.9%) were alive. Conclusion According to our results, SBRT can be considered an effective and safe approach for lung metastasis in oligometastatic patients affected by STS. EP-1636 Role of preoperative radiotherapy in rare retroperitoneal sarcoma P. Navarria 1 , L. Di Brina 1 , E. Clerici 1 , C. Franzese 1 , G. D'Agostino 1 , T. Comito 1 , G. Carta 1 , A. Bertuzzi 2 , V. Quagliuolo 3 , M. Scorsetti 4 1 Humanitas Clinical and Research Center, Radiotherapy and Radiosurgery Department, Via Manzoni 56- 20089 Rozzano – Milan, Italy 2 Humanitas Clinical and Research Center, Medical Oncology Department, Via Manzoni 56- 20089 Rozzano – Milan, Italy 3 Humanitas Clinical and Research Center, Surgical Oncology Department, Via Manzoni 56- 20089 Rozzano – Milan, Italy 4 Humanitas University Department of Biomedical Sciences, Department of Biomedical Sciences, Via Manzoni 113- 20089 Rozzano –Milano, Italy Purpose or Objective Retroperitoneal sarcomas (RPS) are rare tumors and surgery is the standard treatment. Improved local control could be reached through a complete en bloc resection. RPS are usually characterized by an high rate of locoregional and/or distant failure but the main cause of death is represented by local recurrence (LR). For this reason, the use of radiation therapy (RT) for RPS increased over the past decades but no evidences are available about the optimal treatment. The aim of the present evaluation was to analyze the incidence of toxicities and perioperative morbidities in patients who underwent preoperative RT more or less with concurrent chemotherapy (CT). Local, distant failure and overall survival were assessed as well. Material and Methods All patients with histologically proven localized adult type soft tissue sarcoma (STS) of the retroperitoneum or pelvis, any histological grading, with largest diameter > 5 cm, no evidence of distant metastases (DM), received neoadjuvant treatment. Three cycles of CT with high- dose ifosfamide were administered concomitantly. A total dose of 50.4 Gy in 28 fractions was erogated to all the patients. Surgery was scheduled 4–6 weeks after the end of RT. Patients continued to be followed with thorax- abdomen CT scan performed every 4 months for the first 2 years, then every 6 months for the following 3 years, and yearly thereafter.

Results Between 2003 and 2013, 35 patients with resectable localized RPS were treated. Median age was 59.2 years. About half of the patients were male (53.3%). Main histological subtypes were dedifferentiated liposarcoma (34.7%) and well differentiated liposarcoma (22.7%). Median tumor size was 16.4 cm and most of the patients had grade II and III tumors (45.3% and 28%, respectively). Eighteen patients (51%) developed local (33%) or distant (12%) or both local and distant (6%) relapse. Five-year disease free survival (DFS) was 46.6% and overall survival (OS) was 63.2%. Histology and FNCLLC grading were statistically significantly associated with OS (p= 0.024 and p= 0.005, respectively). Thirteen patients developed LR, of whom 5 patients developed concurrent distant metastases (DM). Seven patients developed metastases (DM), of whom the majority to lung. Histological subtypes resulted statistically significantly associated with DM (p: 0.036). All patients completed RT while 4 patients did not completed CT due to hematological toxicity. More than 60% of patients presented grade I-II gastrointestinal toxicity (nausea, vomiting) (N=22). Fatigue was presented by 68% of patients, in 5 patients of grade III. In 3 cases severe perioperative morbidity occurred; in particular 2 patients presented anastomotic leakage, in the other case a retroperitoneal abscess was present. Conclusion Neoadjuvant RT with concomitant CT followed by surgery seems to be an effective approach in the management of RPS. Prospective trials are needed to better understand who are the patients who will benefit the most from this kind of treatment. EP-1637 Early results of spot-scanning proton therapy with hyperthermia in large inoperable sacral chordomas M. Walser 1 , N. Datta 2 , E. Puric 2 , B. Bachtiary 1 , U. Kliebsch 1 , R. Schneider 3 , S. Bodis 2 , D. Weber 1 1 Paul Scherrer Institute PSI, CPT, Villigen PSI, Switzerland 2 Cantonal Hospital Aarau, Radiation Oncology, Aarau, Switzerland 3 Helios Medical Center Schwerin, Radiation Oncology, Schwerin, Germany Purpose or Objective Large inoperable sacral chordomas show unsatisfactory local tumor control rates even when treated with high dose proton therapy (PT). The addition of hyperthermia to radiation therapy leads to improved results in the treatment of sarcomas. The aim of this investigation is to analyze the feasibility and early results of a novel treatment in large inoperable sacral chordomas with high dose PT and local hyperthermia (HT). Material and Methods Eligible patients had histologically proven sacral chordomas. Pencil beam spot scanning proton therapy was delivered with a 250 MeV Cyclotron. Prescribed tumor dose was 70 Gy (RBE) in 28 fractions over 5½ weeks. In 4 (80%) patients, the 70 Gy (RBE) was prescribed to the GTV within a simultaneous integrated boost concept. The PTV, containing the area of possible microscopic disease plus a 7 mm security margin received 56 Gy (RBE). In one patient, the 70 Gy (RBE) was prescribed to the PTV which was the GTV plus 5 mm for CTV and additional 7 mm security margin. Hyperthermia was delivered once a week immediately after proton therapy using the Sigma 60 or Sigma-Eye applicator with