ESTRO 37 Abstract book

ESTRO 37

S441

Following IRB approval, a retrospective review was undertaken of all paediatric patients with DIPG treated at RMH between 01/01/2012 and 01/06 /2017.The primary objective was overall survival (OS). Secondary objectives were progression free survival (PFS), both clinical and radiological, and the proportion receiving re-irradiation. Results 20 children (11 male, 9 females) with DIPG were included. All received 39Gy in 13 fractions as first line treatment, with median age 6.4y (3.6-13.2y), and the median duration of presenting symptoms was 1 m (0.25- 3) : 85% had long tract signs, 90% ataxia and 85% had cranial nerve involvement. Biopsy rate was 10%. Time to start of RT from diagnosis was a median of 8.5 days (1- 43d). 5 patients started RT urgently with a parallel- opposed technique for ≤3 fractions, before switching to a more conformal plan. In both primary radiotherapy and re-radiation, VMAT was used for 58% of patients, CRT used for the remainder. 19 patients have progressed, with a median time to progression: clinical 5.5m (1.4- 14m) & radiological 5.7m (1.4- 13.9m). 9 patients (45%) were retreated with RT upon progression, receiving 20Gy in 10 fractions. The interval from initial RT to reirradiaition was a median of 9.4m (5.95-16.2). 4 patients have received additional chemotherapy, either after initial RT or reirradiation. Median time from progression to death was 6.6m (1.6- 24.3m) and median OS was 12.8m (5.6 – 38.4m). 5 patients progressed within 3 months of initial RT, excluding these poor responders the median overall survival is 17.2m (5.5-38.4m). Conclusion This series of DIPG receiving hypofractionated RT demonstrates OS at least comparable to that previously reported. For those responding to initial radiotherapy reirradiation is a feasible treatment option, which appears to improve outcomes. Further work to evaluate the quality of life for those receiving reirradiation is required to truly understand the clinical benefit. PO-0844 A comparison of outcomes of SBRT versus metastasectomy for pulmonary metastases B.K. Jeong 1 , Y.H. Lee 1 , K.M. Kang 1 , H.S. Choi 2 , H.J. Jeong 1 , J.H. Song 2 , I.S. Jang 3 , S.H. Kim 4 , J.W. Lee 5 , D.Y. Rhee 6 1 Gyeonsang National University Hospital, Radiation Oncology, Jinju-si, Korea Republic of 2 Gyeonsang National University Changwon Hospital, Radiation Oncology, changwon, Korea Republic of 3 Gyeonsang National University Hospital, Thoracic and Cardiovascular Surgery, Jinju-si, Korea Republic of 4 Gyeonsang National University Changwon Hospital, Thoracic and Cardiovascular Surgery, changwon, Korea Republic of 5 Kyungpook National University Medical Center, Radiation oncology, Daegu, Korea Republic of 6 Hanmaeum General Hospital, Emergency Medicine, Jeju, Korea Republic of Purpose or Objective We compared the efficacy of stereotactic body radiotherapy (SBRT) vs. metastasectomy for treating Total 51 patients (median age, 65 years) were included. Twenty-one patients received SBRT using the Cyberknife system (total radiation doses 48–60 Gy delivered in 3–5 equal fractions) and 30 underwent metastasectomy, most (93.3%) with wedge resection. The median follow-up duration was 13.7 months. Local control rate, progression pulmonary metastases. Material and Methods Poster: Clinical track: Palliation

free survival (PFS), and overall survival (OS) were assessed. Results The median tumor size was larger in the SBRT group (2.5 cm) than in the metastasectomy group (1.25 cm; P=0.015). Other synchronous metastases were prevalent in the SBRT group (57.1% vs. 20%; P=0.006). The local control rate was similar in both groups (P=0.163). PFS was longer in patients who underwent metastasectomy than in those who received SBRT (P=0.02), with 1- and 2- year PFS rates of 51.1% and 46% in the former vs. 23.8% and 11.9% in the latter, respectively. The corresponding OS rates were 95% and 81.8% vs. 79.5% and 68.2%, respectively (P=0.534). On multivariate analysis, synchronous metastasis was associated with poor PFS, and tumor size was the most significant factor influencing OS. There were no differences in PFS and OS between the metastasectomy and SBRT groups after dividing patients according to the presence or absence of synchronous metastases..In patients who received SBRT, those with synchronous metastases tended to have poorer PFS rates (P=0.062); in patients who underwent metastasectomy, the corresponding difference in PFS was significant (P=0.038). Among patients treated with SBRT, those with synchronous metastases exhibited significantly poorer OS than those without (P=0.026); the difference in OS was not significant for those who underwent metastasectomy SBRT and metastasectomy for pulmonary metastases produce similar local control and OS outcomes. SBRT is effective and has a broader indication than metastasectomy; however, patients with synchronous metastases are less likely to benefit from local treatment, whether via SBRT or surgery. PO-0845 Histopathological findings after irradiation and re-irradiation of spinal bone metastases with SBRT R. Foerster 1 , B.C.J. Cho 2 , D.K. Fahim 3 , P.C. Gerszten 4 , J.C. Flickinger 5 , I.S. Grills 6 , M.S. Jawad 6 , C.R. Kersh 7 , D. Letourneau 2 , F. Mantel 8 , A. Sahgal 9 , J.H. Shin 10 , B.A. Winey 11 , M. Guckenberger 1 1 University Hospital Zurich, Department of Radiation Oncology, Zurich, Switzerland 2 Princess Margret Cancer Centre, Radiation Medicine Program, Toronto, Canada 3 Wiliam Beaumont Hospital, Department of Neurosurgery, Royal Oak, USA 4 University of Pittsburgh Medical Center, Department of Neurological Surgery, Pittsburgh, USA 5 University of Pittsburgh Medical Center, Department of Radiation Oncology, Pittsburgh, USA 6 Wiliam Beaumont Hospital, Department of Radiation Oncology, Royal Oak, USA 7 Riverside Medical Center, Department of Radiation Oncology, Newport News, USA 8 University Hospital Wuerzburg, Department of Radiation Oncology, Wuerzburg, Germany 9 Sunnybrook Health Sciences Centre, Department of Radiation Oncology, Toronto, Canada 10 Massachusetts General Hospital, Department of Neurosurgery, Boston, USA 11 Massachusetts General Hospital, Department of Radiation Oncology, Boston, USA Purpose or Objective Stereotactic body radiotherapy (SBRT) of the spine provides superior tumor control, but the incidence of vertebral compression fractures is increased and the pathophysiological process underneath is not well understood. Data on histopathological changes, particularly after salvage SBRT following conventional irradiation (sSBRT), are scarce and these patients may be at an increased risk of osteonecrosis. Thus, we sought to (P=0.554). Conclusion