ESTRO 38 Abstract book

S690 ESTRO 38

dyspnea, and financial effect of tumor/treatment) and global QoL. The BN20 is specifically developed for brain patients and assessed visual disorders, motor function, communication deficit, various disease symptoms, treatment, toxicity and future uncertainty. The patients completed the EORTC questionnaires before starting PT, the day of the end of PT and every follow-up consult (1- month, 3-months) until progression of disease. Results The treatment was associated with stability in most of the preselected HRQOL domains. Global health improved over time with a maximum difference of 6 points between baseline and 3-months follow-up. Social functioning and motor dysfunction improved over time with a maximum difference of 8 and 2 points, respectively. We showed only a small not significance decrease in cognitive and emotional functioning. Interestingly, fatigue remained stable during the analysis such as the other preselected domains. Increase of CTV, use of steroids before protontherapy and concomitant chemotherapy are associated with a statistically significantworse QLQ C30_Social, QLQ C30_Physical and BN20_Motor values. Conclusion Re-irradiation with PT for a large recurrence Glioblastoma is a safe treatment without a negative effect on HRQOL until the time of disease progression. EP-1256 Influence of PET-imaging during treatment planning on outcome in meningioma patients K. Kessel 1,2,3 , H. Fischer 1 , T. Voglhuber 1 , C. Diehl 1,2 , C. Straube 1,2 , W. Weber 1 , S.E. Combs 1,2,3 1 Klinikum rechts der Isar- TU München, Department of Radiation Oncology, München, Germany ; 2 Deutsches Konsortium für Translationale Krebsforschung DKTK, Partner Site Munich, München, Germany ; 3 Helmholtz Zentrum München, Institute for Innovative RadiotherapyiRT, München, Germany Purpose or Objective Radiotherapy (RT) is an alternative treatment to surgery for low-grade meningiomas or applied in an adjuvant setting. In high-grade cases, RT after resection is the treatment of choice. RT improved over the years, and modern techniques such as IMRT combined with IGRT increase safety and precision. However, during treatment planning, definition of the planning target volume (PTV) remains challenging, and differentiation between healthy tissue, i.e. meninges, post-operative changes, and residual tumor can be difficult using MR and CT imaging alone. In this study, we evaluated the influence of additional PET-imaging on progression-free (PFS) and overall survival (OS). Material and Methods We analyzed 353 patients with primary RT of meningiomas treated between 1994 and 2017. For analyses, we divided the patients in low-grade (n=282) and high-grade (n=71) meningiomas. Table 1 shows the patient characteristic. Previous resection was performed in an adjuvant setting due to subtotal resection or later due to recurrent tumor growth. Patients were treated with either fractionated stereotactic radiotherapy with a median dose of 54.0 Gy and median single dose of 1.8 Gy, or with radiosurgery with a median dose of 16 Gy. An advanced radiation oncologist delineated PTV based on diagnostic CT and MRI and, if available, additional PET-imaging with either 68Ga-Dotanoc/Dotatoc, F-18 FET (fluroethyltyrosine) or C11 Methionin tracer.

Gemelli ART, Roma, Italy ; 2 Policlinico A.Gemelli, Hematology Department, Roma, Italy

Purpose or Objective One of the main limiting factor of a whole brain radiation therapy (WBRT) is the neurocognitive functions (NCFs) decline, which is mainly caused by the radiation-induced injury to the hippocampus. This study evaluates the correlation between the site of (Primary Central Nervous System Lymphoma) PCNSL lesions and the hippocampal region to generate evidence to routinely spare of the hippocampus during a WBRT. Material and Methods Patients with pathologically proven PCNSL and MRI image pre-treatment were retrospectively reviewed. T1- weighted, axial MR image were imported on Varian Eclipse treatment planning system and registered with the simulation CT. The hippocampus as well as each PCNSL lesions were contoured. Three dimensional envelopes surrounding the hippocampus were generated adding 5, 10, and 15 mm. The minimum margin of 5 mm was considered for systematic setup error and dose fall-off between whole brain clinical target volume and the hippocampus. Results Between 2005 and 2018, 36 pts with 57 lesions were eligible for this study. PCNSL lesions’ locations were: deep brain structures (26%), parietal lobe (23%), frontal lobe (19%), temporal lobe (14%), occipital lobe (7%), brainstem (5%), other sites (6%). In 18/57 lesions (31.6%) the distance from the hippocampus region was less than 5 mm and seven of them (12.3%) involved the hippocampus. Lesions over 15 mm from the hippocampus were observed in 30 cases (52.6%), while only the 15,8% was between 5 and 15 mm. Conclusion Our data don’t support the routinely sparing of the hippocampal region in PCNSL. It could be considered in selected patients, when the spatial distribution of lesions is far more than 5 mm from the hippocampus. EP-1255 Health-Related Quality of Life in large recurrence Glioblastoma treated with protontherapy D. Scartoni 1 , D. Amelio 1 , F. Fellin 1 , I. Giacomelli 1 , M. Schwarz 1 , M. Amichetti 1 1 Centro di Protonterapia, Protontherapy, Trento, Italy Purpose or Objective Protontherapy (PT) could minimize the risk of side effects compared to conventional photon therapy and therefore reduce the possible detrimental effect on QoL of re- irradiation. We report the effect of re-irradiation with active scanning PT of large recurrence GBM in terms of quality of life scored by the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ)––C30 and EORTC Quality of Life Questionnaire Brain Cancer Module (QLQ-BN20). Material and Methods Between January 2015 and October 2018 thirty patients with recurrence GBM were re-irradiated with active scanning PT. All patients had been previously treated with photon radiotherapy (60 Gy) with concomitant and adjuvant temozolomide (TMZ). Median age and Karnofsky performance status at re-irradiation were 53 years (range, 30-68 years) and 80%, (range, 60-100%), respectively. Target definition was based on CT, MR, and 18F-DOPA PET imaging. Median CTV (clinical target volume) was 69 cc (range, 11-259 cc). All patients received 36 GyRBE (RBE: relative biologic effectiveness) in 18 fractions, with concomitant TMZ in 7 patients (25%). Subscales within the EORTC QLQ-C30 include five functional scales (physical, role, emotional, cognitive, and social), three symptoms scales (nausea, vomiting, and fatigue), six single-item scales (insomnia, appetite loss, constipation, diarrhea,