ESTRO 37 Abstract book

S670

ESTRO 37

EP-1201 Outcomes of patients with brain metastases from uncommon primaries treated with radiosurgery A. Dasgupta 1 , F. Moraes 1 , J. Winter 1 , H. Raziee 1 , C. Coolens 1 , G. Zadeh 2 , P. Kongkham 2 , M. Bernstein 2 , T. Conrad 1 , N. Laperriere 1 , B.A. Millar 1 , A. Berlin 1 , D.B. Shultz 1 1 Princess Margaret Cancer Centre, Radiation Oncology, Toronto, Canada 2 Toronto Western Hospital, Neurosurgery, Toronto, Canada Purpose or Objective There have been a limited number of reports describing the outcomes of brain metastasis (BM) arising from certain primary tumours treated with stereotactic radiosurgery (SRS). Our objective was to study the outcomes of such patients treated with gammaknife (GK) A prospective registry of 1465 patients treated with SRS between January 2008 and September 2016 was screened to identify 98 patients. Dose was prescribed per institutional guidelines and ranged from 15 to 21 Gy depending upon the target volume and functional area. Demographics, treatment details and outcomes were evaluated, including local failure (LF) and distant brain failure (DF). Statistical analysis was performed using SAS system (version 9.4). Kaplan-Meier product limit method was used for survival analysis, univariate analysis done by log-rank test and multivariate analysis done by Cox regression model. Results Patients were sub classified into group 1: head and neck (5), gynaecologic (21) or genitourinary (3) primary tumours; and group 2: gastro-intestinal (GI) (39), endocrine (14), and sarcoma (16). Performance scores were ECOG 0 or 1 in 84% and extracranial (EC) disease was controlled in 46%. Whole brain radiotherapy (WBRT) had been administered previously to 17% of patients and 64% had received chemotherapy prior to SRS. At a median follow up of 9 months (range 2 to 115 months), 14 patients had experienced a LF (14.3%). Thirty-nine experienced DF (40%) and 47 (48%) died. Median time to LF was 8 months (range 1 to 110 months) and median time to DF was 7 months (range 1 to 103 months). Local control (LC) with SRS was 88%, and 73%, at 1, and 2 years, respectively. EC disease status was the only factor to impact LC (p=.02) or DF free survival (p=.004). Median overall survival (OS) was 9 months (range 2 -115). One- year OS was significantly better in group 1 compared to group 2 (92% vs. 51%, p=.02). There was a trend towards improved one-year OS when EC disease was controlled (70% vs. 57%, p=.06). No factors were significantly associated with LC, DF, or OS on multivariate analysis. at a single institution. Material and Methods

Conclusion Patients with metastases from head neck, gynaecological and genitourinary malignancies experience improved OS compared to GI, sarcoma, or endocrine tumours. SRS provides excellent control of BM from uncommon sites. EC status is an important determinant of survival and the use of WBRT and systemic therapies need to be explored in prospective manner to improve disease control. EP-1202 Radiosurgical decompression for benign perioptic tumors causing compressive cranial neuropathy Y.H. Cho 1 , K. Yoon 1 , D. Lee 1 , D. Kwon 1 1 Asan Medical Center- Univ of Ulsan, Neurosurgery, Seoul, Korea Republic of Purpose or Objective Several studies have reported the efficacy and safety of hypofractionated stereotactic radiosurgery (hSRS) in the treatment of benign perioptic tumors. This study went further and evaluated the feasibility of hSRS in the treatment of those causing compressive cranial neuropathies (CCNs) among perioptic tumors with special consideration of functional improvement. Material and Methods Twenty-six patients with CCNs (CN II=19; CN III/IV/VI=9; CN V=3) caused by perioptic tumors underwent hSRS between 2011 and 2015. hSRS was delivered in 5 fractions with a median marginal dose of 27.8 Gy (≈14 Gy in a single fraction, assuming an α/β of 3) to a tumor volume of 8.2±8.3 cm3. Results All tumors except 1 shrank after treatment, with a mean volume decrease of 35% (range, 4%-84%) during the mean follow-up period of 20 months. In 19 patients (38 eyes) with compressive optic neuropathy, vision improved in 55.3% of eyes (n = 21), was unchanged in 36.8% (n = 14), and worsened in 7.9% (n = 3) (2.6% after excluding 2 eyes deteriorated due to transient tumor swelling). A higher conformity index (p = 0.034) and volume of the optic apparatus receiving > 23.0 Gy (p =0 .019) were associated with greater tumor shrinkage. A greater decrease in tumor volume (p = 0.035) was associated with a better improvement in vision. Ophthalmoplegia and facial hypesthesia improved in 6 of 9 (66.7%) and 3 of 3 (100%) patients, respectively. There was no newly developed neurological deficit. Conclusion Decompressive SRS for benign perioptic tumors causing CCN is feasible using hypofractionation, representing a useful alternative to microsurgical resection. EP-1203 Post-radiation T2 changes in MRI brain: Is there a dose-effect relation? N. Khataniar 1 , B. Sarkar 1 , R. Gupta 2 , S. Agrawal 1 , B. Mohanti 1 , A. Munshi 1 1 Fortis Memorial Research Institute, Radiation Oncology, Gurgaon, India