Abstract book - ESTRO meets Asia

S69 ESTRO meets Asia 2018

PO-170 Does low junction Craniospinal irradiation(CSI) treated with VMAT improves organs at risk dose . P. Chaudhari 1,1 1 Fortis Memorial research Institute, Radiation Oncology, Gurgaon- Haryana, India Purpose or Objective To evaluate the Dosimetric parameters for low junction craniospinal irradiation (CSI) treated with volumetric modulated arc therapy (VMAT) technique. Material and Methods 11 treatment plans of patients who received CSI by low junction between cranial and spinal field at C4-C5 level treated by VMAT were retrieved retrospectively. The CSI dose for standard risk patients was 23.4Gy/13# followed by boost to post op cavity 30.6Gy/17#. High risk patients received 35Gy/21# CSI followed by boost to post op bed 19.8Gy/11#. The spinal cord boost to the involved level was given upto 45Gy. The Dosimetric parameters were noted. Brainstem Dmax, Chiasm Dmax, Optic Nerve Dmax, bilateral Eye Dmax, Bilateral cochlea Dmax, Thyroid Dmean and Dmax, Pharynx Dmax, oral cavity Dmax, oesophagus Dmax, B/L lung Dmean, Heart Dmean, B/L kidney Dmean, Liver Dmean, Bowel Bag Dmax and Dmean, Bladder Dmax and doses to gonads were noted and median dose was calculated. Results Median PTV volume for Phase I (craniospinal RT) was 1854.1cc, median volume of Post op cavity boost(brain) was 59.5cc and median volume of spine boost in high risk patients was 43.4cc.The median doses to Organs at risk achieved were: brainstem Dmax 56.13Gy (range25.5- 62.7Gy), Chiasm Dmax 48.16Gy(range 25.3-57.7Gy), right Optic nerve Dmax 39.15Gy(range 25.01-49.08Gy), left Optic Nerve Dmax 40.14Gy(range24.5-55.5Gy), right eye Dmax 28.4Gy(range 10.4-38.3Gy), left eye Dmax 30.18Gy(range 12-36.5Gy),right cochlea Dmax 39.3Gy(range 25.2-47.8Gy), left cochlea Dmax 43.14Gy(range 25.1-48.4Gy), thyroid Dmax 16.3Gy(range 10.3-26.04Gy), Thyroid Dmean11.6Gy (range 8.18- 19.7Gy), oral cavity Dmax 15.9Gy(range 12.4- 16.2Gy),oesophagus Dmax 22.58Gy(range 19.3-29.3Gy), maximaum dose to pharynx was 21.8Gy(range 19.5- 29.4Gy), right lung Dmean 6.7Gy(range 2.71-9.04Gy), left lung Dmean 5.17Gy( range 1.54-7.8Gy), heart Dmean 7.04Gy(range 4.01-12.3Gy), right kidney Dmean3.3Gy( range 1.9-6.7Gy), left kidney Dmean 3.04Gy(range 1.2- 6.8Gy), Dmax to the testis ranged from 0.18 to 2.7Gy, liver dmean 5.54Gy(range2.8-7.28Gy), Bowel Bag Dmax7.8Gy( range 5.8-45.19Gy), bowel bag dmean 2.17Gy( range 3.53- 9.89Gy), Bladder2.17Gy(range 1.18-29.3) Conclusion CSI using VMAT technique with low junction achieves lower dose to the swallowing structures like oral cavity, pharynx and oesophagus and improves tolerance to large treatment field. PO-171 Clinical outcome of hypofractionated stereotactic radiotherapy for inoperable skull base meningioma

Material and Methods Twenty patients with intracranial skull base meningioma underwent hypofractionated stereotactic radiotherapy (HSRT) by using Brain Lab stereotactic radiotherapy system between 2004 and 2017. All patients were inoperable and diagnosed pathologically as benign meningioma (19 patients; grade I, 1 patients; grade II). A mean tumor volume of meningioma was 11.2 cc (3.3 – 31.8 cc). Over 10 cc of tumor volume was 9 cases. A median follow-up was 61 months (2 – 210 months). A mean total dose of 35.9 + 4.64 Gy was prescribed in a mean fractionation was 9.5 + 4.09. Tumor response was radiographycally evaluated with computed tomography and magnetic resonance imaging. Results The 3-year local control was 100 %, and 5-yaer local control was 85.7 %, respectively. Local recurrence after stereotactic radiotherapy was seen in 2 patients. All symptoms were recovered in patients who had visual impairment after HSRT. Grade 3 late adverse effects were not observed in the follow-up period. Conclusion HSRT was safe and effective treatment for inoperable skull base benign meningioma. HSRT was also considered to be effective for >10 cc meningioma. An optimal dose and fraction is a subject of future investigation for meningioma. PO-172 Prospective neurocognitive and oncological outcomes in newly-diagnosed primary CNS Iymphoma patients S.Y. Lin 1 , C. Chi-Cheng 2 , T. Din-Li 1 , P. Ping-Ching 1 , S. Yi- Liang 1 1 Chang Gung Memorial Hospital, Department of Radiation Oncology, Taoyuan, Taiwan 2 Chang Gung Memorial Hospital, Department of Neurosurgery, Taoyuan, Taiwan Purpose or Objective Conventional treatment for treating primary central nervous system lymphoma (PCNSL) has consisted of either whole-brain radiotherapy (WBRT) or methotrexate (MTX)- based combined modality therapy. However, delayed treatment-related cognitive sequelae have emerged as a significant debilitating complication of combined modality treatment in PCNSL patients, especially when effective treatment can result in disease control and greater survival. At our institute, a prospective observational cohort study with longitudinal assessments of neurocognitive functions (NCFs), neuroimaging, and activities of daily living in newly-diagnosed PCNSL patients was undertaken. Material and Methods Neurobehavioral outcomes were integrated into this prospective study and a battery of neuropsychological measures was used to evaluate NCFs. The battery is composed of ten standardized NCF tests, representing four domains sensitive to disease and treatment effects (executive function, attention, verbal memory, psychomotor speed), and activities of daily living. Results Totally 15 patients with newly-diagnosed PCNSL including two cases with primary intraocular lymphoma were consecutively enrolled from February 2014 to January 2018. Comparing the NCF scores between the baseline and post-treatment intervals, neurobehavioral outcomes consistently remained improving or stable in almost each domain evaluated in this study. Specifically, the scores of executive functions based on Paced Auditory Serial Addition Test (PACT) significantly got improving between the baseline and post-chemoradiation assessment (Wilcoxon signed-rank test, p = 0.016). Conclusion Under the multidisciplinary treatment guidelines for treating patients with newly-diagnosed primary CNS

D. Takafumi Yamano 1 , D. Takeo Takahashi 1 , D. Keiichiro Nishimura 1 , D. Kana Washizu 1 , D. Rikana Soda 1 , D. Hiromasa Kurosaki 1 , D. Nobuko Utsumi 1 , D. Munefumi Shimbo 1 , D. Shogo Hatanaka 1 , D. Masatsugu Haryu 1

1 Saitama Medical Center- Saitama Medical University, Department of Radiation Oncology, Kawagoe, Japan Purpose or Objective The aim of this study is to retrospectively investigate the outcome of linac-based fractionated stereotactic radiotherapy for inoperable and intracranial skull base benign meningioma in our institute.