ESTRO 38 Abstract book

S675 ESTRO 38

showed control of the irradiated BMs (3 CR, 3 PR, 4 SD according to the RANO criteria) at last follow-up. Conclusion SIDCA has been successfully implemented for patients with multiple BMs (and is also in routine use for patients with single BMs, as it can considerably decrease the duration of RS planning, verification and reporting). The irradiation of multiple BMs up to 4cm from the isocentre with the same fractionation scheme and a 1 mm margin is feasible, efficient and effective in daily practice. Local control rates > 80% are equivalent to those achieved in our centre with RS for single BMs. EP-1224 Re-Irradiation in Recurrent Gliomas: Treatment outcome and Prognostic factors M. Mukherjee 1 , J. Bhattacharya 1 , T. Shahid 1 , V. Kontham 1 , R. Rajan 1 , R. Talukdar 1 , A. De 1 1 Apollo Gleneagles Hospital, Radiation Oncology, Kolkata, India Purpose or Objective Gliomas have diverse prognoses that differ primarily depending on histologic subtype, grade and molecular marker expression. Even after aggressive multimodal treatment, most gliomas eventually recur. Treatment options for recurrent gliomas include surgery, chemotherapy, and re-irradiation. We sought to review our institutional experience with re-irradiation in the management of recurrent gliomas. Material and Methods We retrospectively reviewed 31 patients with recurrent or progressive gliomas who received re-irradiation between January 2012 and December 2016. Majority (20 patients) constituted High Grade Glioma. (Grade III and IV). Though the recurrence was more in Grade IV Glioma but these patients were not included in our analysis because of their poor performance status and Re-RT was not feasible in them. All the patients were assessed for Re-Surgery. Re- irradiation was offered to recurrent glioma patients with good performance status and at least 6 months had passed after initial radiotherapy (RT). All the patients were treated after doing planning CT Scan (Non-Contrast) and MRI of Brain (3 D FSPGR sequence) with I.V contrast and images were fused for target delineation. Target volume was delineation was kept conservative and the mean volume was 80 cc (50 to 140 cc). Technique of Radiotherapy was IMRT/VMAT and fractionation used was conventional. 11 patients were treated with concurrent oral Tab TMZ and 1 patient was treated with Inj Bevacizumab, 2 weekly cycle. Results Out of 31 patients, 11 patients were found to be fit for Re- Surgery but only 8 patients agreed to do so. All the patients received Re-Radiation. Median doses of re- irradiation and initial RT were 45.0 Gy and 59.4 Gy, respectively. The median time interval between initial RT and re-irradiation was 18 months. The median PFS and OS after re-irradiation were 3 and 7 months respectively. 12- month OS rate was 40%. 3 patients developed radiation necrosis and needed prolonged steroid therapy. In univariate analysis, Karnofsky performance status (KPS) ≥70 ( p <0.001), re-irradiation dose ≥45 Gy ( p =0.040), and longer time interval between initial RT and re-irradiation ( p =0.040) were associated with improved OS. In multivariate analysis, KPS ( p =0.030) and length of time interval between initial RT and re-irradiation ( p =0.048) were important predictors of OS. Use of TMZ did not show any benefit. Molecular markers were not available for most of the patients and hence correlation could not be done. Conclusion Re-irradiation in conjunction with surgery could be a salvage treatment for very selected recurrent glioma patients with good performance status. Re-irradiation was associated with only modest palliative and survival

to tumor bed was applied in addition to 54-60 Gy/30 fractions chemoradiation with temozolomide, with a total of 69 Gy/30 fractions. Univariate and multivariate analyses were utilized for the possible prognostic factors of overall survival (OS). Results A total of 51 AA patients were identified and 42 patients were enrolled in final analysis by using 1:2 propensity score matching of karnofsky performance status and extent of resection among the AA patients. The median follow up time is 41 months. CCRT-SIB is associated with better OS (hazard ratio HR: 0.32, 95% CI: 0.11- 0.96; p =0.042) in univariate analysis. On the contrary, contrast-enhanced AA had worse OS (HR: 6.12, 95% CI: 1.33-28.22; p =0.02). The 3-year PFS rate and OS rate in CCRT-SIB was 59.1% and 75%. Acute and long term neurotoxicity was similar. Conclusion Our study revealed better OS and PFS in the AA patients treated with CCRT-SIB. Further prospective randomized trial is encouraged to define the role of CCRT-SIB. EP-1223 Clinical experience and outcomes of radiosurgery with a single isocentre for 2-10 brain metastases. S. Rogers 1 , N. Lomax 1 , S. Alonso 1 , B. Eberle 1 , S. Gomez Ordonez 1 , J. Schürkens 1 , E. Rabe 1 , J. Fandino 2 , O. Riesterer 1 , G. Lutters 1 , S. Bodis 1 1 Kantonsspital Aarau, Radiation Oncology- KSA-KSB, Purpose or Objective Commercial software has recently become available to facilitate radiosurgery (RS) treatment planning and delivery by using a single isocentre for multiple brain metastases (BMs). Patients with multiple BMs represent 38% of our BM RS case load and have increased by 50% in the last 2 years. We have reviewed our initial experience of the feasibility and efficacy of the single isocentre dynamic conformal arc (SIDCA) technique. Material and Methods Methods : 51 patients, each with 2-10 BMs, have been treated on a Novalis STx Linac in our centre to date. 20 consecutive patients, planned with SIDCA (Elements Multiple Metastases v1.5, Brainlab), were included in the analysis. The standard dose prescription was 1 x 20 Gy, (V20Gy = 99%, with Dmax 115-130%), a 1 mm planning margin with a maximum of 10 cm 3 brain-GTV to receive 10 Gy per metastasis. Results The 20 patients had a total of 72 BMs. 70% of patients had NSCLC, the female to male ratio was 11:9 and the median age was 70 years (51-81 yrs). In 8/20 patients, BMs were grouped into 2-3 isocentres for either clinical indications (e.g. fractionated RS due to volume or postoperatively) or rotational uncertainties (> 4cm from isocentre) rather than increase the planning margin. Dose prescriptions were 52/72 BMs: 1 x 20 Gy, 7/72: 1 x 15-18 Gy, 13/72: 5 x 5-6 Gy according to patient and tumour factors. Mean single fraction PTV dose (59 BMs) was 22.1 Gy (15.8-23.95 Gy) and mean fractionated PTV dose (13 BMs) was 32.93 Gy (27.41-33.85 Gy). For single fractions, median PTV volume was 0.29 cm 3 (0.09-2.78 cm 3 ) with a median total PTV volume of 1.08 cm 3 (0.36-7.74 cm 3 ) per patient. For fractionated RS, these median volumes were 3.95 cm 3 (2.36-11.9 cm 3 ) and 10.2 cm 3 (6.3-22.9 cm 3 ) respectively. 5/20 patients had previous or simultaneous RS to single metastases or a surgical cavity, which increased the irradiated volumes and therefore sum plans were generated (Eclipse, Varian). At 6 week clinical follow-up, 3 patients still required steroids. 5 patients developed distant brain failure 3-6 mths after RS, of whom 3 received further SIDCA RS to the new BMs. 11 patients have died (med OS 6 mths, 2-13 mths); of these 9/11 patients (82%), Aarau, Switzerland ; 2 Kantonsspital Aarau, Neurosurgery- KSA-KSB, Aarau, Switzerland