ESTRO 2020 Abstract Book

S464 ESTRO 2020

Italy ; 2 IRCSS CRO Aviano, Medical Physics, Aviano, Italy ; 3 Azienda Sanitaria Universitaria Integrata di Udine, Neurosurgery, Udine, Italy Purpose or Objective Glioblastoma is the most common primary malignant brain tumor in adults, counting 16% of all primary CNS tumors, with poor prognosis. Almost all patients undergo disease progression/recurrence: actually no standard of care is established for recurrent or progressive GBM (rGBM). Treatment approaches for tumor recurrences include second surgery, re-irradiation, systemic therapies, combined modality and supportive cares and have to consider tumor size and location, previous treatments, age, Karnofsky performance score (KPS), patterns of relapse, and prognostic factors. We retrospectively investigated the feasibility of a second irradiation with or without chemotherapy for these patients. Material and Methods From January 2011 until March 2018, thirty patients with recurrence of high-grade gliomas (12 with grade III gliomas, 18 with grade IV gliomas) received a median re- irradiation dose of 36 Gy (Range 34 – 41.1 Gy) with conventional fractionation (1.8 – 2 Gy/die), after initial postoperative radiotherapy or combined radiochemotherapy. Median age at the recurrence was 53 years (range 21-75 years). Twelve patients received chemotherapy (Temozolomide) concomitant to re- irradiation and adjuvant, 8 patients received re-irradiation and then adjuvant chemotherapy (CCNU), 10 patients received re-irradiation alone. Overall survival was calculated with Kaplan-Meier method. We carried out a neurocognitive evaluation with psycho-oncologist collaboration and patients followed a neurocognitive rehabilitation therapy. Results Mean time between radiation therapies was 36 months (range 6-176 months). All patients carried out re- irradiation, with no cases of Grade ≥3 toxicity, particularly in the twenty patients subjected to concomitant and/or adjuvant chemotherapy. After median follow up of 15 months, median overall survival results 8 months (range 1- 95 months) and was 44% after 1 years and 29% after 2 years of follow up. The patients’ group treated with concomitant chemoradiotherapy (Temozolomide) presents a better median overall survival compared to group treated with re-irradiation alone (16 months vs. 7 months); overall survival at 1 year was 57.1% vs 35.7% and at 2 years was 47.6% vs. 26.8%. From neurocognitive evaluation (Minimental test and quality of life evaluation) we report a good feasibility of re-irradiation, with good compliance to neurocognitive rehabilitation therapy Conclusion In our experience re-irradiation associated with concomitant chemotherapy (Temozolomide) for recurrence high grade gliomas represents a good treatment option, with a better OS after 1 and 2 years respect re-irradiation alone or with adjuvant chemotherapy and presents a good neurocognitive tolerance. Patients selection is important to determinate whom could benefit from these approach. Prospective trials are required to confirm these preliminary findings PO-0864 SRS alone of brain metastases with unfavorable prognostic factors M. Harat 1,2 , M. Blok 3 1 Franciszek Lukaszczyk Memorial Oncology Center, Radiosurgery and Radiotherapy of CNS, Bydgoszcz, Poland ; 2 Collegium Medicum- Nicolaus Copernicus University, Oncology and Brachytherapy, Bydgoszcz, Poland ; 3 Franciszek Lukaszczyk Memorial Oncology Center, Radiotherapy, Bydgoszcz, Poland

selection. Prospective studies are needed to clarify the best treatment strategies for the various subgroups of patients with BMs from BC particularly in the era of increasing use of new systemic therapies. PO-0862 Clinical outcome of anaplastic oligodendroglioma treated with adjuvant radiotherapy and temozolomide M. Rastogi 1 , A. K Gandhi 1 , R. Khurana 1 , R. Hadi 1 , S. Sapru 1 , S. P Mishra 1 , A. K Srivastava 1 , A. Bharati 1 , S. Rath 1 , S. S Nanda 1 , H. B Singh 1 , S. Kumar 1 , N. P Singh 1 , N. Husain 2 , M. Husain 3 , D. K Singh 4 1 Dr. Ram Manohar Lohia Institute of Medical Sciences, Radiation Oncology, Lucknow, India ; 2 Dr. Ram Manohar Lohia Institute of Medical Sciences, Pathology, Lucknow, India ; 3 Sahara Hospital, Neurosurgery, Lucknow, India ; 4 Dr. Ram Manohar Lohia Institute of Medical Sciences, Neurosurgery, Lucknow, India Purpose or Objective Anaplastic oligodendroglioma (AOG) are diverse group of tumors with variable molecular profiles. Although, PCV chemotherapy has been shown to improve outcome, toxicity and compliance limits its use. Temozolomide (TMZ) is widely used as an alternative. We aimed to evaluate the role of TMZ in the management of AOG patients treated at our institution retrospectively. Material and Methods Data of 48 AOG patients treated at our institution between 2012-2018 were retrieved from our departmental archives. All patients underwent a maximal safe resection with a confirmed histology of AOG. Post-operative radiotherapy (PORT) consisted of 60 Gray in 30 fractions delivered with 3-dimensional conformal radiotherapy on a linear accelerator. TMZ (75 mg/m 2 daily) was used during concurrent phase and 150-200 mg/m 2 was used during adjuvant phase (150 mg/m 2 in first cycle and then escalated to 200 mg/m 2 ) if tolerated well. Kaplan Meier method was used for survival analysis. Results Median age of the patient was 46 years (30-65 years). Male: Female ratio was 40:8. 22 (45.8%) patients presented with seizure. 31 (64.5%) patients underwent a gross total excision, 11 (22.9%) had a subtotal resection and 6 had decompression only. Median MIB labelling index was 24 (range: 6-43). 1p/19q co-deletion status was available in 20 (41.6%) patients and was co-deleted in 16 (80%) of these patients. Median radiotherapy dose was 60 Gray (range 46- 60 Gray). 29 (60.4%) patients received concurrent, 24 (50%) received both concurrent and adjuvant and 5 received only adjuvant TMZ. Median number of adjuvant TMZ cycles were 6 (range: 2-12). Rates of grade III-IV thrombocytopenia and neutropenia in patients receiving TMZ was 13.8 % and 6.89% patients respectively. Median follow up was 28 months. Estimated median progression free survival (PFS) was noted to be 4.8 years. 3-year progression free survival (PFS) and overall survival was 68% and 76% respectively. Univariate analysis revealed better PFS for patients presenting with seizure (HR=0.74; 95% CI: 0.64-0.89; p=0.038). Rest of the factors like age, extent of surgery or 1p/19q co-deletion status did not statistically impact survival. Conclusion Adjuvant and Concurrent TMZ is feasible and tolerable in patients of AOG treated with maximal safe resection and PORT. Results of randomized trial evaluating PCV versus TMZ in this setting would better allow us to tailor our treatment. Adaptation of management as per molecular profile of AOG is evolving. PO-0863 Radiochemotherapy retreatment in high grade giomas recurrences A. Caroli 1 , L. Vinante 1 , P. Chiovati 2 , T. Ius 3 , M. Skrap 3 , M. Arcicasa 1 1 IRCSS CRO Aviano, Department of Radiotherapy, Aviano,