ESTRO 37 Abstract book

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ESTRO 37

Purpose or Objective To evaluate the acute toxicity and efficacy of reirradiation with hypofraccionated stereotactic radiotherapy in patients with histological proved gliomas Material and Methods From July 2012 to January 2017, we treated and analyzed 30 patients with high-grade recurrence GII-IV gliomas. All treatment decisions were based on multidisciplinary approach, all patients signed consent form before treatment In all cases countouring was based on MRI and CT fused images, and in two patients we used metionina C11 PET- CT for improving delimitation the gross tumor volumen (GTV). Treatment was performed with the Novalis ExacTrac image guided system which consists of a non invasive frame-based mask system that allows us to perform stereotactic treatments. Treatment plan was performed on Iplan-net (v. 4.1) with either multiple non coplanar conformal beams or dynamic conformal arcs, with 3Dconformal radiation therapy or IMRT if it was needed. Novalis IGRT is based on two X-ray images that fuse bone structures with DRR reconstructed from CT simulation scan. Robotic 6D coach corrects with submillimeter accuracy translational and rotational errors before treatment. Results Medium age was 50,8 years. 17 patients were male and 13 female. Primary tumor at diagnose was grade II glioma in 8 patients, and grade III-IV in 22 patients. Median time to reirradiation was 32,5 months; in low grade gliomas median time to reirradiation was 60,5 months, being 22 months in high grade tumors. Recurrences were identified on the basis of radiographic presence of tumor progression on T1;T2 weighted MRI. 13 patients underwent surgery before reirradiation. Medium PTV volume was 107,56 cm3 (12 -240cm). The prescribed dose was 30 Gy in 5 fractions or 40 Gy in 10 fractions depending on the size and location of the tumor. All patients maintained prophylactic dexametasone for at least two weeks after the treatment completion. No patients demonstrated clinically significant acute morbidity, and all patients were able to complete the prescribed radiation dose without interruption. No patient required hospitalization or surgery for early acute or delayed toxicity.The median survival from the reirradiation was 11 months.Overall survival of the sample was 34 months; 49.5 months in grade II, and 30.6months in high grade. Conclusion Hypofraccionated reirradiation seems feasible and well tolerated. No significant toxicity was observed. EP-1213 Tumor bed adyuvant irradiation with stereotactic radiotherapy after surgery in brain metastases M. Lopez Gonzalez 1 , O. Hernando Requejo 1 , R. Ciervide 1 , X. Chen 1 , A. Montero Luis 1 , J. Valero 1 , P. Fernandez- Leton 2 , C. Rubio Rodriguez 1 1 Hospital Universitario Madrid Sanchinarro - Grupo Hospital de Madrid, radiation oncologist, Madrid, Spain 2 Hospital Universitario Madrid Sanchinarro - Grupo Hospital de Madrid, Physicist, Madrid, Spain Purpose or Objective Adjuvant hypofractionated stereotactic radiotherapy (HFSRT) tumor bed after resection of brain metastases is a strategy to delay or avoid whole-brain irradiation (WBRT) and its associated toxicities. Our purpose is to evaluate local control of resected brain metastasis

There were no further grade 3 or higher late toxicities. Currently, absolute tumor control is 100%. Despite the short follow-up radiological reduction was registered in 30% of pts. Of the three pts (30%) with functional hearing (GR Grade 1 or 2), all (100%) retained serviceable hearing ability. Absolute normal facial and trigeminal nerve function preservation rates were 80% and 90%. Conclusion Active beam scanning PT is feasible and safe treatment for pts with untreated VS. Longer follow-up is necessary to assess definitive efficacy and toxicity. EP-1211 High-dose vs conventional radiotherapy for high-grade glioma: A propensity score-matched analysis W. Takahashi 1 , A. Nomoto 1 , K. Okuma 1 , S. Sawayanagi 1 , H. Yamashita 1 , K. Nakagawa 1 1 University of Tokyo, Radiology, Tokyo, Japan Purpose or Objective To improve local control, high-dose conformal radiotherapy (HRT) was formerly used to treat high-grade glioma in our institution. The present study compared HRT with conventional-dose radiotherapy (CRT) in patients with anaplastic astrocytoma (AA) and glioblastoma (GBM). Material and Methods We identified patients diagnosed with AA or GBM from 1977 to 2015 who were treated with either HRT (> 70 Gy) or CRT (50-70Gy) in our institution. The progression free survival (PFS) and overall survival (OS) of patients receiving HRT vs CRT was compared using the log-rank test, multivariable Cox proportional hazards regression, and propensity score matching (PSM). For PSM, we identified eligible patients having enough clinical information and constructed a propensity score matched cohort (1:1 for HRT vs CRT) to balance observable potential confounders. Results Among 305 included patients, 31 patients with AA and 80 patients with GBM received HRT and 62 patients with AA and 132 patients with GBM received CRT. Predictors for receipt of HRT included supratentorial tumor location, incomplete resection, no concurrent temozolomide and old year of diagnosis (all P < 0.03). Median doses of 80 Gy (range, 70–94 Gy) and 60 Gy (range, 51–68 Gy) were delivered in HRT and CRT, respectively. No significant difference in PFS and OS were observed between HRT and CRT (median PFS = 15.6 vs 12.7 months, log-rank P = 0.69, and median OS = 20.6 vs 18.5 months, P = 0.47). Cox proportional hazards model showed that survival predictors included age (<60 years), Karnofsky performance status (>/=80%), AA, concurrent temozolomide, and extent of resection (subtotal or gross total resection). After matching, 67 sub-pairs of 134 patients were generated in post-PSM cohort with well balance in observed co-variables. No significant differences in progression-free survival (PFS) and overall survival (OS) were observed between 2 groups (P = 0.15 We compared the clinical outcomes between HRT and CRT for AA and GBM. HRT is not associated with improved OS and PFS. EP-1212 Hypofraccionated Stereotactic Reirradiation In Patients With High-Grade Gliomas M. Lopez Gonzalez 1 , R. Ciervide 1 , O. Hernando Requejo 1 , E. Sanchez Saugar 1 , A. Montero Luis 1 , M. Garcia-Aranda 1 , B. Alvarez 1 , J. Garcia Ruiz Zorrilla 2 , C. Rubio Rodriguez 1 1 Hospital Universitario Madrid Sanchinarro - Grupo Hospital de Madrid, radiation oncologist, Madrid, Spain 2 Hospital Universitario Madrid Sanchinarro - Grupo Hospital de Madrid, Physicist, Madrid, Spain and 0.09). Conclusion

treated with HFSRT. Material and Methods

From October 2011 to January 2017, 30 patients with intracranial metastasis who were treated with adyuvant postoperative HFSRT. CTV contouring was based on MRI