ESTRO 2022 - Abstract Book

S208

Abstract book

ESTRO 2022

Conclusion A robust data framework for combining ASL perfusion data with RT dosimetric data has been developed. Early data indicate that reductions in grey matter CBF persist outside the target volume over one year after RT for glioma, and are dose dependent. This has implications for radiotherapy planning and post-treatment toxicity surveillance and potentially its management. Further analysis of the full patient cohort will be undertaken and available for presentation.

PD-0246 The role of adjuvant RT in craniopharyngioma in 2021 WHO new classification of CNS tumor era

B.M. Lee 1 , J. Cho 1 , J.H. Chang 2 , S. Kang 2 , E. Kim 2 , J.H. Moon 2 , S.S. Ahn 3 , Y.W. Park 3 , C. Suh 4 , H.I. Yoon 1

1 Yonsei cancer center, Radiation oncology, Seoul, Korea Republic of; 2 Severance Hospital, Neurosurgery, Seoul, Korea Republic of; 3 Severance Hospital, Radiology, Seoul, Korea Republic of; 4 CHA Bundang Medical Center, Radiation Oncology, Seongnam, Korea Republic of Purpose or Objective Craniopharyngioma, newly classified into two distinct tumors in 2021 WHO classification, has controversies in adjuvant treatment due to frequent recurrence after surgery. Administration of adjuvant external beam radiotherapy (EBRT) can increase the risk of developing long-them sequelae. Stereotactic radiosurgery (SRS) has been applied to lower treatment related toxicity. The aim of this study was to compare the treatment outcomes and toxicity according to the types of craniopharyngioma and adjuvant treatment. Materials and Methods We analyzed patients who underwent tumor removal for craniopharyngioma from 2000 to 2017. A total of 153 patients were included, with 27 patients and 20 patients receiving adjuvant fractionated EBRT and SRS, respectively. We compared the local failure free rate (LFFR), progression free survival (PFS) and overall survival (OS) between groups that received adjuvant fractionated EBRT, SRS and surveillance. The patients were stratified into two groups according to the 2021 WHO classification of CNS tumor: adamantinomatous craniopharyngioma (ACP) and papillary craniopharyngioma (PCP). The treatment outcome according to adjuvant treatment in ACP and PCP were also compared. Treatment-related toxicity was also analyzed. Results The median follow up period was 77.7 months. Five-year LFFR was 71.5% for SRS and 70.8% for surveillance, whereas there was no local recurrence after adjuvant fractionated EBRT ( p=0.005 ). None of the patients in the adjuvant fractionated EBRT group experienced either progression or death within 5 years. However, the 5-year PFS was 60.0% and 64.6% in SRS group and surveillance group, respectively ( p=0.002 ). Both in ACP and PCP, the treatment outcome significantly differed according to adjuvant treatment. The adjuvant fractionated EBRT enhanced the LFFR compared to SRS and surveillance group in both ACP and PCP. The treatment related toxicity was tolerable in this group. Conclusion Regarding LFFR, the adjuvant fractionated EBRT is superior to SRS and surveillance. The adjuvant fractionated EBRT also enhanced LFFR in both ACP and PCP. L. Solway 1 , M. Hickman 2 , S. Meade 2 , H. Benghiat 2 , H. Augustus 2 , R. Stange 2 , T. Jackson 2 , G. Heyes 2 , P. Monksfield 3 , A. Kay 4 , R. Irving 3 , S. Chavda 5 , A. Hartley 2 , P. Sanghera 2 1 University Hospital Birmingham, Oncology, Birmingham, United Kingdom; 2 Univeristy Hospital Birmingham, Oncology, Birmingham, United Kingdom; 3 Univeristy Hospital Birmingham, ENT, Birmingham, United Kingdom; 4 Univeristy Hospital Birmingham, Neurosurgery, Birmingham, United Kingdom; 5 Univeristy Hospital Birmingham, Radiology, Birmingham, United Kingdom Purpose or Objective Stereotactic radiotherapy (SRT) is routinely used to treat Vestibular Schwannomas (VS) to avoid the need for surgical intervention. It is generally recommended that VS causing brainstem compression are surgically treated. However, there are some patients who decline surgery or are deemed medically unfit who undergo treatment with SRT. There is debate amongst clinicians about the best way to treat these large VS and practice varies between 12Gy in 1#, 18Gy in 3# or more prolonged fractionation. Materials and Methods All patients undergoing CyberKnife Radiotherapy for VS at a regional centre were identified from a prospective database. Treated lesions over 4cc with at least 2 years of follow up were included for this analysis. All patients were given a key worker contact number to report toxicity events and records from outpatient visits were used to establish toxicity data. Toxicity was documented for facial and trigeminal nerve via CTCAE v4 grading and timing of occurrence and interventions required to manage symptoms were recorded. Any other acute or late G3 or 4 toxicity was also recorded. Results 48 patients were included for analysis treated between 07/2013 and 08/2019. Treatment volume varied from 4.05-11.61cc (mean 5.66cc). 19 (40%) lesions were treated with 3# and 29 (60%) lesions were treated with 1#. The mean size in the 3 vs. 1# groups was 6.44cc (range 4.06cc-11.61cc) vs. 5.15cc (range 4.05cc-6.67cc) (p=0.0025).In total 7 (15%) patient PD-0247 Giant Vestibular Schwannomas – 1 versus 3 fractions?