ESTRO 36 Abstract Book

S332 ESTRO 36 _______________________________________________________________________________________________

PO-0634 Irradiation of Subventricular Zone in Glioblastoma: Its Impact on Tumor Progression and Survival F. Sert 1 , S. Hoca 1 , S. Kamer 1 , Y. Anacak 1 1 Ege University Medical School&Hospital, Radiation Oncology, Izmir, Turkey Purpose or Objective Subventricular zone (SVZ) is a paired brain structure situated throughout the lateral walls of the lateral ventricles, a known site of neurogenesis and self-renewing neurons in the adult brain. Some current theories propose that brain tumour stem cells originating from subventricular zone (SVZ) play a role in progression of high-grade gliomas. Since almost all glioblastomas progress locally despite aggressive surgery and radiotherapy, recur within the high-dose irradiation volume in most cases, the theory of tumor cell migration from SVZ is interesting to explore. Irradiation of SVZ supposed to kill brain tumor stem cells which may alter tumour progression and survival. The purpose of this study is to evaluate the impact of the radiation dose to SVZ on progression rates and overall survival in glioblastoma. Material and Methods Study population consisted of 80 glioblastoma patients (23 females, 57 males) with a median age of 55.5 (21-75) who were treated from January 2012 to December 2014. All patients underwent surgery followed by adjuvant radiotherapy (60 Gy/30 fractions) and concomitant / adjuvant temozolomid. Bilateral SVZ were contoured on MRI images and registered to planning CT slices. Target volumes and organs at risk were also contoured. Conformal radiotherapy with 3-4 fields or IMRT with 1-2 volumetric arcs were used for planning. Median doses for ipsilateral, contralateral and bilateral SVZ were recorded and relations with progression and survival were analyzed using two threshold values at 40 Gy and 50 Gy. Analyses were performed after a median follow-up of 13 months. Results Median progression free survival (PFS) was 10 months (2- 36) and overall survival (OS) was 12 months (3-48). The unfavorable prognostic factors affecting PFS were tumor extending to ventricles (p<0.01), ipsilateral SVZ doses >50 Gy (p<0.05), and contralateral SVZ doses >50 Gy (p<0.05). The unfavorable prognostic factors affecting OS were tumor extending to ventricles (p<0.001), contralateral SVZ doses >40 Gy (p<0.05) and bilateral SVZ doses >40 Gy (p<0.05). In multivariate analysis of prognostic factors, tumor extending to ventricles was the only unfavorable factor for both PFS (p<0.001) and OS (p<0.001). Conclusion PFS and OS were shorter in the patients in whom tumor was extending to ventricles and in those where SVZ received at least 40-50 Gy. The data of this study is supports the previous studies showing an inverse correlation between irradiation of SVZ and prognosis. With the present data we can only speculate that those tumors extending deep into the lateral ventricles likely to be larger in size, closer to nearby sensitive structures, and not amenable to total resection. Radiation volumes should cover some parts of SVZ and lateral ventricles to give the prescribed dose to in those unfavorable tumors, which may explain the inverse correlation with SVZ irradiation and survival. Further research is required to clarify the role of brain tumor stem cells locates at SVZ in the prognosis of high-grade gliomas. PO-0635 Can psychological support during RT improve distress, mood or quality of life in CNS tumor patients? L. Dinapoli 1 , S. Chiesa 1 , N. Dinapoli 1 , F. Beghella Bartoli 1 , S. Bracci 1 , M. Massaccesi 1 , A. Tenore 1 , A. Pesce 1 , V. Valentini 1 , M. Balducci 1 1 UCSC, Radiation Oncology Department Gemelli-ART, Roma, Italy

Purpose or Objective Patients with CNS tumor often show at diagnosis significant levels of distress, anxiety and depression, which may increase during radiotherapy (RT), for side effects (headache, hair loss, cognitive deficits) or psychological impact on everyday life (absence from work, caregivers’ burden). These factors could influence negatively patients’ quality of life (QoL) during the entire RT course. The objective of this study is to evaluate the effect of a psychological support offered to patients throughout RT on distress, anxiety, depression and QoL. Material and Methods Consecutive patients with CNS tumors who underwent RT with radical intent were included between January and September 2016. Psychological support was available for all patients. Distress Thermometer (DT), Hospital Anxiety and Depression Scale (HADS) and Functional Assessment of Cancer Therapy (FACT)-Br were used to evaluate emotional distress, mood and QoL, respectively. The tests were self-administered at the beginning (T0), the middle (T1), the end (T2) of the RT course and three months after the end of RT (T3). Statistical analysis of tests’ scores was performed by means of Wilcoxon test for paired samples. Results Twenty-eight patients (12 male and 16 female, median age 56, range 20-72 years) who underwent radical RT for CNS tumors were included. Radiotherapy was post- operative in all patients and was delivered up to a median total dose of 60 (range 50-66) Gy. Twenty (71.4%) patients received concurrent chemotherapy with temozolomide. All 28 patients underwent the T0, T1 and T2 evaluation. Data collection after three months (T3) is still ongoing. At T0, 17/28 patients (60.7%) were emotionally distressed (DT score≥4, DT median score=7); at T1, 20/28 (71.4%) patients had significant emotional distress and at T2, 16/28 (57.1%) patients had significant emotional distress. At T0, 9/28 patients (32.1%) showed anxiety/depression (HADS score≥14, HADS median score=20); at T1, 11/28 (39.3%) and at T2, 6/28 (21.4%) patients had significant anxiety and depression. During RT, in patients who were distressed at baseline (17/28), DT score significantly improved at T2 (median DT score 7 and 5, at T0 and T2 respectively, p<0.05)(fig 1). In patients who were anxious and depressed at baseline (9/28), HADS score did not significantly change during RT. Regarding QoL, statistical analysis on FACT-Br (T0 Vs T2) showed stable scores in Social, Functional, Physical and Symptoms subscales and an improvement in Emotional Well-Being subscale (median Emotional Well-Being score 18 and 19, at T0 and T2 respectively, p=0.002).