ESTRO 2020 Abstract book

S523 ESTRO 2020

how many patients receive futile WBRT and characterize the patients in this group. Material and Methods Patients with NSCLC and BM referred to WBRT in 2016 to 2018 at Herlev Hospital are included. Clinical information regarding patient and disease characteristics, treatment and survival are retrieved. Overall survival was estimated using Kaplan-Meier from WBRT start. Variables possibly influencing overall survival are calculated using Cox proportional hazards regression model. Results 97 patients are included in the study. Thirty-two (33%) of the patients presented with BM at diagnosis. Median overall survival was 86 days (95% CI 72-110). Overall survival rates at 6 months and 1 year were 28.9% (95% CI 21.1-39.5) and 18.6 (95% CI 12.2-28.2), respectively. Survival based on type of systemic treatment (immune checkpoint inhibitors, targeted agents, chemotherapy or no treatment) is shown in the figure.

PO-0893 Radiation therapy in meningioma- single center prospective and retrospective analysis I. Hadi 1 , P. Yanchovski 1 , R. Bodensohn 1 , S. Corradini 1 , C. Schichor 2 , C. Belka 1 , M. Niyazi 1 1 University Hospital LMU, Department of Radiation Oncology, Munich, Germany ; 2 University Hospital LMU, Department of Neurosurgery, Munich, Germany Purpose or Objective Meningioma is the most common primary intracranial tumor in adults. However, management of meningioma has not changed significantly until recently. Therefore, we analyzed patients, who underwent radiation therapy at our institution both prospectively and retrospectively. Material and Methods Every patient with meningioma who received radiation therapy at our department was included. All patients were diagnosed with MRI of the brain and 68 Ga-DOTATATE PET/CT prior to radiotherapy. Visual test, audiometry and hormonal testing were performed based on the localization of meningioma. These tests were carried out at baseline and follow up. The Kaplan-Meier method was used to analyze local control and log-rank test was used to test for differences between groups. Results This is an interim analysis of 78 out of 227 patients with meningioma, who have been treated at our institution between 2011 and 2019. Fifty-six female (71.8%) and 22 male (28.2%) patients with a median follow-up of 11 months (range: 3-42 months) were included in this first analysis. Meningioma WHO°I was found in 63 patients (80.8%), WHO°II in 14 patients (17.9%), and WHO°III in 1 patient (1.3%). WHO °I patients were treated with a median single dose of 1.8Gy to a median total dose of 54.0Gy. WHO°II and °III patients received radiotherapy in a median single dose of 1.8Gy to a median total dose of 59.4Gy. One- and 2-year local control in patients with WHO°I meningioma after radiotherapy were both 100% respectively. Twelve-months LC in patients with WHO°II meningioma was 87.5%. Radiotherapy was well tolerated, with no CTCAE °III was reported. The most common toxicity were headache (n=21; 26.9%), subjective visual impairment (n=16; 20.5%), and fatigue (n=32, 41.0%). Conclusion Radiotherapy of meningioma provides excellent local control especially in WHO°I meningioma. Further follow up and investigations are needed to analyze patients with recurrent WHO°I or any WHO°II and °III meningioma. PO-0894 Survival in patients with NSCLC with brain metastases treated with WBRT F. Sundbye 1 , G. Persson 1 , K. Skougaard 1 1 Herlev Hospital, Oncology, Copenhagen, Denmark Purpose or Objective Up to 30% of patients with NSCLC develop brain metastases (BM). The prognosis for this patient group is poor. In case of five or less BM, guidelines recommend stereotactic radiosurgery, if more WBRT. Multiple studies have shown WBRT to be associated with progressing neurocognitive side effects and to reduce quality of life significantly. For patients with a short life expectancy it is important to consider treatment with supportive care alone. In a non- inferiority study (QUARTZ) 538 patients with metastatic NSCLC were randomized between WBRT and best supportive care. Primary endpoint was quality-adjusted life-years. In the study there was no difference between the two groups and a median survival of approx. 9 weeks. The study group was criticized for including patients in a poor performance status. In this retrospective study we want to examine if the median overall survival of patients treated with WBRT in our institution is at the same level as in the QUARTZ study. Furthermore, we want to examine

A performance status of 2 or higher (p<0.0001) and shorter WBRT fractionation schedule (p<0.0001) had a negative impact on overall survival. Extracranial control, systemic treatment with both immune checkpoint inhibitors (p<0.0001) and targeted agents (p=0.040) as well as local treatment of BM with stereotactic radiosurgery (p=0.015) were significantly associated with better overall survival. On multivariate analysis (see table), high performance status (p<0.0001), extracranial control (p=0.0007), treatment with immune checkpoint inhibitors (p=0.0001) and stereotactic radiosurgery (p=0.014) were significantly correlated with overall survival.