ESTRO 2020 Abstract book

S520 ESTRO 2020

up was 4.5 months (range, 0-75 months) after the start of radiotherapy. All patients underwent whole brain radiotherapy extended to the caudal margin of the second vertebral body with a median single dose of 2.5Gy (range, 1.8-3.0Gy) to a median total dose of 35.0Gy (range, 6.0- 46.0Gy). The majority of patients (n=39, 97.5%) were deceased with a median overall survival of 4.0 months (range, 1.3-6.7months). On univariate analysis, better patients’ performance status (ECOG) improved overall survival (OS) significantly (p=0.031). Symptoms related to intracranial pressure (ICP) or neurological deficits were associated with inferior OS. One year-OS in patients with ICP was 9% and 24.1% in patients without ICP (p=0.034). Histology was not a significant prognostic factor in our cohort (p=0.946). The most common acute toxicities during WBRT were nausea (CTC°3 in 2 patients) and headache (CTC°3 in 2 patients). Improvement or stabilization of neurological deficits after WBRT was observed in 9 patients, one patient did not recover from neurological deficits. Information regarding improvement or stabilization of neurological deficits was not sufficient in 30 patients. Conclusion Our analysis demonstrated that LM from NSCLC and breast cancer were associated with poor overall survival. ECOG and the presence of neurological deficits were significant prognostic factors. WBRT is well tolerated and can provide relief of symptoms. However, further investigations are needed to verify which treatments are the most suitable for different types of LM. PO-0887 Recurrence of glioblastoma with or without gross total resection followed by chemoradiotherapy S. Tsuruoka 1 , Y. Hamamoto 1 , I. Hirofumi 1 , T. Noriko 1 , N. Kei 1 , M. Teruhito 1 1 Ehime University Hospital, Radiology, Ehime, Japan Purpose or Objective Glioblastoma (GBM) is the most malignant tumor of the central nervous system even with optimal tri-modality therapy (surgery, radiotherapy (RT) and temozolomide). Gross total resection (GTR) is one of the good prognostic factors. In this retrospective study, we compared recurrence patterns between patients with or without GTR. Material and Methods From April 2009 to December 2017, 102 patients with GBM were treated with RT plus temozolomide in our institution. Among them, a patient who failed to complete RT was excluded, and 101 patients were analyzed in this study. The patients treated with GTR (GTR) and those without GTR (non-GTR) were 57 and 44, respectively. Conventionally fractionated RT (60 Gy at 2 Gy/fr) was performed for 93 patients, and hypofractionated RT (40.05 Gy at 2.67Gy/fr) was performed for the rest. Temozolomide only, temozolomide plus bevacizumab, and temozolomide plus interferon β were performed for 87, 11 and 3 patients, respectively. Overall survival (OS) and progression-free survival were compared using the Kaplan– Meier method. Therecurrence patterns of GTR and non- GTR were compared using the Fisher’s exact test. Results The median age was 66 years old (7 to 89). The median follow-up was 14.3 months (0.7 to 94 months). The median overall survival (OS) and progression free survival (PFS) were 18.3 months and 7.4 months, respectively. The median OS and PFS in GTR were significantly better than those in non-GTR (OS: 23.5 vs 9.3 months, p = 0.002, PFS: 11.4 vs 3.2 months, p = 0.007). Overall, 74 (73%) patients experienced tumor progression: 39 (68%) in GTR and 35 (80%) in non-GTR. The recurrence patterns were local, distant brain, and meningeal dissemination in 56, 18 and 9 patients, respectively. The incidence of dissemination in GTR was significantly lower in non-GTR (6% vs 16%, p = 0.039). Local and distant brain recurrences occurred This abstract has been withdrawn

institution. Twenty seven pts underwent MRI early before, during, at the end as well as 1 month after the treatment and were included in the analysis. All pts received 36 GyRBE in 18 fractions.ED was evaluated and contoured on 108 MRI scans using T2 and FLAIR sequences (5 mm thickness). ED volume (in cc) was quantified as any T2 and FLAIR changes excluding the Gross Tumor Volume. We analyzed the temporal change of ED at the baseline, mid- therapy, at the end, and 1 month after treatment. Mean values of differently delineated ED volumes were compared each other by paired Student’s t-test; p < 0.05 was considered significant. Results Twenty two pts were treated for recurrent glioblastoma and 5 for anaplastic gliomas. Median (Med) CTV was 80 cc (range, 12-259). Med ED volume at the baseline, mid- therapy, at the end, and 1 month after treatment was 62 (range 7-265), 79 (range 9-242),82 (range 10-194),77 cc (range 9-200), respectively. During treatment ED increased in 19 pts (70%) and decreased in 8 (30%). Such increase of ED volume was statistically significant both at mid-therapy and at the end of the treatment with respect to baseline (p=0,004 and 0,01, respectively) but it was associated with mild symptoms only in 10 pts (37%) and was controlled with modification of steroids dose. One month after treatment ED decreased in 11 pts (40%), increased in 10 (37%) and was stable in 6 (22%). As a consequence, mean ED values 1 month after treatment did not significantly differ with respect to baseline. Seven out of 10 pts (70%) with increased ED needed modification of steroids dose. During follow up 3 pts (13%) developed radionecrosis (RN - diagnosed at imaging) with mild symptoms controlled with steroids. In pts who presented RN, ED volume increased of 169% during treatment. In pts who registered increased ED without RN, the mean ED volume increase during the treatment was of 96,98 %. Pts who presented RN had a mean CTV volume of 56.47 cc. Conclusion PT re-irradiation of rHGG is frequently associated with a significant increase of ED volume during treatment. Such variation often does not translate into clinical worsening and does not need modification of steroid use.ED volume decreases after the end of the treatment.ED volume during treatment increase more in pts who experience RN after re-irradiation and could predict the development of RN.CTV volume does not seem to predict the development of RN. PO-0886 Leptomeningeal metastases of breast and lung cancer- a retrospective analysis I. Hadi 1 , D. Hofmann 1 , R. Bodensohn 1 , M. Niyazi 1 , C. Belka 1 , S. Nachbichler 1 1 University Hospital LMU, Department of Radiation Oncology, Munich, Germany Purpose or Objective Leptomeningeal metastases (LM) might occur in progressive or late stages of solid tumors. Diagnosis and therapy remain challenging due to non-specific symptoms and limited therapeutic options. This retrospective analysis investigated outcome and prognostic factors of patients with LM from breast and lung cancer, who had received radiotherapy at our Institution. Material and Methods Patients with newly diagnosed LM from breast and lung cancer who received radiotherapy at our department were retrieved from the institutional database. Patients treated between 2001 and 2014 were included. The Kaplan-Meier method was performed to analyze survival and log-rank test was used to test differences between groups. Results Forty patients (7 male and 33 female) with a median age of 63 years (range, 31-78 years) were included. LM from breast cancer was found in 25 patients, LM from NSCLC (adenocarcinoma) was found in 15 patients. Median follow-