ESTRO 36 Abstract Book

S609 ESTRO 36 2017 _______________________________________________________________________________________________

contrast-enhancing regions. Inter-rater reliability was evaluated by the intraclass correlation coefficient (ICC). BTVs with a threshold of 1.6 and a union of these BTVs with the consensus MRI-based GTVs were compared to the consensus GTVs only. OTP-Masterplan ® was used for treatment planning. Dice coefficients and conformity indices were used for comparing the consensus GTVs and BTVs and for the union of consensus GTV plus BTV with the original planning target volume (PTV). Results PET-MR imaging conducted prior to re-irradiation of 7 high-grade glioma patients (2 WHO grade III, 5 WHO grade IV) was used for this planning study with three independent raters. Median follow-up from initial diagnosis was 52 months and median post-recurrence survival 13 months. Median age at the beginning of re- irradiation was 54 years and median KPS 80. Median post- recurrence progression-free survival from the beginning of re-irradiation was 8 months. Six patients received bevacizumab concomitantly to re-irradiation and 1 patient temozolomide. Median GTV volume ranged from 35 to 40.5 cc, median consensus GTV volume of all three raters was 41.8 cc, median BTV 36.6 cc and the union of consensus GTV and BTV in median 59.3 cc. The ICC between the raters was on average measures 0.96, 0.96 and 0.97. The dice coefficient between the consensus GTV and the BTV was in median 0.61 and the conformity index 0.44. The dice coefficient between the union of consensus GTV and BTV with a margin of 8 mm and the original PTV was median 0.84 and the conformity index in median 0.73. Conclusion PET-MRI derived BTVs may help to adjust the margin at treatment planning of recurrent high-grade glioma re- irradiation and reduce inter-rater variability. The most prominent advantage of this imaging modality is the „one- stop-shop' including two coregistered imaging modalities of high quality. EP-1125 Concomitant temozolomide therapy improves survival outcome of patients with multifocal glioblastoma M. Syed 1 , J. Liermann 1 , T. Sprave 1 , V. Verma 2 , J. Rieber 1 , S.B. Harrabi 1 , N. Bougatf 3 , D. Bernhardt 1 , A. Mohr 1 , S. Rieken 1 , J. Debus 1 , S. Adeberg 1 1 Universitaetsklinik Heidelberg, Department of Radiation Oncology, Heidelberg, Germany 2 University of Nebraska Medical Center, Department of Radiation Oncology, Omaha, USA 3 University Hospital Heidelberg, Heidelberg Ion-Beam Therapy Center HIT, Heidelberg, Germany Purpose or Objective Concomitant temozolomide (TMZ) therapy has been established as first line treatment of malignant gliomas after several studies had shown better survival outcomes. These studies have largely been performed with patients with unifocal lesions. Our study aims to investigate the role of temozolomide therapy in multifocal glioblastoma (GBM) along with radiotherapy by comparing differences in survival rates of patients with unifocal GBM (uGBM) and multifocal GBM (mGBM). Material and Methods We retrospectively analyzed 265 patients with primary GBM undergoing radiation therapy at the Department of Radiation Oncology, Heidelberg University Hospital between 2004 and 2013. Of these, 202 (76%) were uGBMs and 63 (24%) were mGBMs. 133 (65%) with uGBM and 43 (68%) with mGBM received concomitant treatment with TMZ. First, progression-free survival (PFS) and overall survival (OS) between groups were compared using the Kaplan-Meier method. Second, univariate and multivariate Cox proportional hazards regression was applied to discern prognostic factors including TMZ with PFS and OS in the cohorts. Results

Hundred ninety-five patients (73%) experienced tumor progression on follow-up MRI scans performed after radiation therapy. Patients with mGBM experienced significantly worse OS of 11.5 months (range 1.6 - 25 months) as compared to patients with uGBM with an OS of 14.8 months (range 1 – 55.9 months) ( p=0.032) , with similar patient characteristics in both Groups. There were no significant differences in PFS between the respective groups (6.5 versus 6.6 months, p=0.750). Concomitant TMZ therapy was associated with significantly better OS in mGBM ( 8.3 vs 14.2 months, p = 0.006 ) and uGBM (11.7 vs 17.0 months, p<0.001). Univariate and multivariate analyses for OS revealed a negative prognostic effect for multifocal disease (p<0.001) and a positive prognostic effect for concomitant TMZ treatment in mGBM (p=0.008) and uGBM (p < 0.001). Conclusion Patients with mGBM generally experienced significantly worse overall survival than patients with uGBM after radiation therapy. Concomitant TMZ treatment improved OS of patients with mGBM and uGBM by approximately five months. EP-1126 Whole brain radiotherapy of breast cancer brain metastases: intracranial progression and prognosis. D. Ou 1 , L. Cao 1 , C. Xu 1 , J. Chen 1 1 Ruijin Hospital- Shanghai Jiaotong University School of Medicine, Radiation Oncology, Shanghai, China Purpose or Objective Despite the increasing systemic treatment for breast cancer (BC), CNS metastases represent one of most aggressive conditions of metastatic disease. The prognosis became very diverse with regard to molecular subtypes of the primary disease. The current study aims to assess the survival benefit and pattern of intracranial progress of BC patients with brain metastasis (BM) after whole-brain A total of 79 consecutive BCBM, who were diagnosed and treated with WBRT between Jan 2010 and Mar 2016 were studied. All of them were diagnosed with primary invasive ductal carcinoma. Molecular subtypes were defined in 77 patients, as following: Luminal A-like (n=14), Luminal B- like (n=26), HER-2 positive non-luminal (n=13) and Triple Negative (TN) (n=24). Results The median patient age at the diagnosis of BM was 49 years (range 22–77 years) and the median KPS at BM was 80. The median time to BM (TTBM) was 36 months (range 0-232 months). Sixty-five patients received upfront WBRT and 14 received WBRT subsequent to SBRT. Systemic treatment were administered to 50 patients after WBRT, including endocrine therapy in 10 patients, chemotherapy in 42 patients, anti-HER2 therapy in 14 patients. The time to BM in patients with HER-2 positive was shorter than Luminal-A like (20.5 vs. 89.0months ， p <0.001). Median overall survival (OS) after BM was significantly associated with Breast-GPA 0-1, 1.5-2, 2.5-3 and 3.5-4 were 4.3, 14.0, 14.8 and18.2 months, respectively (p =0.012, fig A). Univariate analysis found that KPS at the diagnosis of BM, infra-tentorial metastases, total doses and systemic therapy after WBRT were significantly associated with OS after BM (p< 0.05). The multivariate analysis showed infra-tentorial metastases, total doses and systemic therapy after WBRT were independent prognostic factors for OS after BM(p <0.05). The median OS was significantly improved in HER-2 + patients receiving anti-HER2 therapy after WBRT (25.4 vs. 5.6 months, p = 0.040). Also, the median OS was significantly improved in GPA 1.0-2.0 patients who received upfront WBRT (14 vs. 7.9 months, p = 0.012). The proportion of occurrence of intracranial progress for radiotherapy (WBRT). Material and Methods