ESTRO 2020 Abstract Book

S473 ESTRO 2020

single fraction or 24Gy in 3 daily fractions. Local recurrence occurred in 32(17.3%) patients. Median,6months,1-year-LC were 86 months(95%CI36-86), 87.2%±2.8, 77.8%±4.1. No severe neurological toxicity occurred. Median,6months,1-year-BDF were 23 months(95%CI9-44), 66.4%±3.9, 55.3%±4.5. Median,6months,1-year-OS were 7 months(95%CI 6-9), 52.7%±3.6, 33%±3.5. No severe neurological toxicity occurred. Stage at diagnosis, Karnofsky Performance Status (KPS), presence and number of extracranial metastases, and disease-specific-graded-prognostic- assessment (DS-GPA) score were observed as conditioning survival. Conclusion SRS/HSRS have proven to be an effective local treatment for BMCRC. A careful evaluation of prognostic factors as well as a multidisciplinary evaluation is a valid aid to manage the optimal therapeutic strategy for CTC patients with BMs. PO-0881 Visual outcomes in anterior visual pathway meningioma with standard vs hypofractionated FSR regimens L. Zach 1 , A. Agami 2 , R. Huna Bar On 3 , O. Nissim 4 , R. Spigelman 5 1 Sheba Medical Center, Oncology Institute, Rehovot, Israel ; 2 Tel Aviv University, medical School, Tel Aviv, Israel ; 3 Sheba Medical center, Ophtalmology, Ramat Gan, Israel ; 4 Sheba Medical Center, Neuro-surgery, Ramat Gan, Israel ; 5 Sheba Medical Center, Neurosurgery, Ramat Gan, Israel Purpose or Objective Most anterior visual pathway meningiomas (AVPM) are benign and slow-growing tumors. They may still affect visual functions, including visual acuity (VA) and visual field (VF). Due to their eloquent location, most are treated non-surgically by fractionated stereotactic radiotherapy (FSR). This high precision type of radiotherapy is aimed at preventing tumor progression and visual functions deterioration, but FSR in itself may affect visual functions. Preferred treatment regimen (safety and effectiveness) is debatable: most cases are treated with standard fractionation (FSRT) – 28-30 fractions of 1.8-2 Gray (Gy). Recent technological advances and an aim to shorten total treatment length led the use of hypo-fractionationated regimens (hSRT) – 3-5 fractions of 5-9Gy. We aimed to valuate the correlation between radiotherapy regimen (FSRT vs hSRT) in AVPM and visual functions (VA, VF) outcome at the last compared to the pre-treatment neuro-ophthalmologic evaluation. Material and Methods We conducted a retrospective cohort analysis among AVPM cases treated with FSR during 2004-2015 at Sheba Medical Center. We compared FSRT and hSRT regarding visual functions (VA, VF) outcomes at the last neuroophthalmologic evaluation. VA was determined by logarithm of minimum angle of resolution (LogMAR). VF was determined by mean deviation (MD). Clinically relevant change in VA was defined as 0.2 LogMAR. Results Out of 155 patients with AVPM treated in our center in the study period, 48 patients (13 in hSRT, 35 in FSRT) had enough information and were included in the analysis. Median follow-up was 55 mo. No significant difference between the two groups was evident regarding either LogMAR (p=0.327) or MD (p=0.935) of involved eye at the last evaluation. Nevertheless, 6 (17%) patients in the FSRT group experienced clinically relevant VA deterioration in involved eye, compared with 6 (46%) in hSRT (p=0.061). Conclusion While this study is based on a limited sample and did not confirm a statistically significant correlation between radiotherapy regimen and visual functions outcomes, it suggests that FSRT may be associated with less visual

toxicity compared to hSRT and the last should be used cautiously in this group of patients. PO-0882 Single centre review of the survival benefit and toxicity of PCI in Small Cell Lung Cancer S. Forner 1 , I. Vasiliadou 1 , J. Little 1 , M. Fenton 1 , S. Goyal 1 , R. Burcombe 1 , P. Brulinski 1 , T. Sevitt 1 1 Kent Oncology Centre, Clinical Oncology, Maidstone, United Kingdom Purpose or Objective Small cell lung cancer (SCLC) is associated with a poor prognosis; median survival is 7 months (1), and brain metastases are present in 50-60% of patients (2). Prophylactic Cranial Irradiation (PCI) is standard treatment for limited stage disease and considered for patients with extensive disease who are fit enough for treatment and have responded to chemotherapy. PCI has been shown to improve survival by 5.4% at 3 years (2). We reviewed the use of PCI at KOC to assess survival and morbidity data. Material and Methods A retrospective analysis of all patients treated for small cell lung cancer at the Kent Oncology Centre between 2004 and 2008 was performed. Toxicity data was gathered from clinical assessments during and following treatment. Survival data was collected from electronic records and GP databases. Data was analysed and statistical analyses performed using SPSS software. Results Of 107 patients identified, 24 had limited stage and 83 had extensive stage disease. Median survival for the total population was 10.3 months (12.8 months for limited stage disease and 9.4 months for extensive stage disease). Performance status (PS) significantly affected prognosis: median survival was 1 month for patients who were PS 3, compared with 12.8 months for patients PS 0-1 (p=0.003). Subgroup analysis revealed an additional 3.2 months median survival benefit for patients treated with consolidation thoracic irradiation. Excluding the patients with brain metastases at diagnosis, the addition of PCI significantly improved median overall survival from 6.3 months to 15 months (p=0.001) (see Graph 1). This improvement was seen in both PS 0-1 and PS 2 patient groups, with an improvement in median survival of 7.4 and 4.6 months respectively. Lethargy was the most common adverse effect, experienced by 74% of patients, followed by nausea in 33%. Confusion and memory impairment was seen in 8%. A general trend of increasing toxicity rates with increasing patient age and with hypofractionation was observed. Graph 1: Kaplan–Meier Curve Comparing Median Survival in patients with and without PCI

Conclusion In this cohort, PCI confers a substantial improvement in median survival in small cell lung cancer, with acceptable