ESTRO 37 Abstract book

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ESTRO 37

EP-1193 SRS to cavity post resection of intracranial metastases. A single centre experience 2013-2016 M. Higgins 1 , O. Burke 1 , K. Nugent 1 , M. Dunne 1 , C. Skourou 1 , D. Fitzpatrick 1 , C. Faul 1 1 St. Luke's Radiation Oncology Network- Dublin, Radiation Oncology, Dublin, Ireland Purpose or Objective Stereotactic Radio Surgery (SRS) to the surgical cavity post resection of brain metastases (BM) has been shown to have similar overall survival (OS) and local control rates when compared to Whole Brain Radiotherapy (WBRT). In this study, we reviewed the local control (LC) rates and the OS post adjuvant SRS at one institution. Material and Methods A retrospective review was conducted of adjuvant intracranial SRS at Beaumont Hospital, Dublin, Ireland, between September 2013 and December 2016. Patient records, treatment plans, and follow up diagnostic images were reviewed. Local failure was MRI defined. Statistical Analysis was undertaken using chi- square tests and Fisher’s exact tests and Mann-Whitney tests. The Kaplan-Meier method was used to estimate survival times and the log-rank test was used to compare differences in survival. Results 48 patients with 49 surgical cavities received adjuvant SRS in this period. Results summarised in table 1.

50.2) months in pts treated with surgery and adjuvant IG- IMRT-CT and 8.1 (1.8-36.8) months in pts treated with radical IG-IMRT. This results compares favorably with those of GBM survival in US and Roa’s trial. Median survival was 9.8 months in pts treated with 40 Gy/ 15 fr and 15.9 months in pts treated with 60 Gy/ 30 fr. Pts with only one lesion had a better median survival that pts with multifocal GBM : 15.4 vs 10.2 months. Time to progression was 6.6(1.8-47.5) months in adjuvant treatments and 3.3(0.2-34.1) months in radical treatments. Acute toxicity were: headache:G1=10.0%, G2=2.2%; dizziness: G1=3.3%,G2=2.2%; nausea: G1= 10.0%,G2= 1.1%; hearing loss: G1=3.3%,G2=1.1%; Ophtalmic: G1=10.0%,G2=2.2%; Cognitive(subjective): G1=5.6%,G2=2.2%; Haematologic: G1=4.6%,G2=4.6%, G3=4.6%,G4=1.5%; Alopecia: G1=31%,G2=2.2%. Late toxicities were evaluable in 74 pts and no G3 toxicities were registered. Headache was: G1= 1.1%, G2= 1.1%; dizziness G1= 2,2%; fatigue G1=6.8%, ophthalmic: G1=1.1%;cognitive(subjective):G1=2.2%;G2=1.1% Conclusion OS and PFS in GBM pts is enhanced by surgery and concomitant CT. Other prognostic factors for OS in our pts: multifocal lesions and RT TD. IG-IMRT ensured a low acute and late toxicity. EP-1192 Dexamethasone-related adrenal insufficiency in patients with brain and skull base tumours. H. Benghiat 1 , P. Sanghera 1 , D. Stange 1 , P. Nightingale 2 , A. Hartley 1 , M. O'Reilly 3 , N. Nundall 1 , D. Spooner 1 , G. Cruickshank 4 , A. Toogood 3 1 Hall-Edwards Radiotherapy Research Group- Queen Elizabeth Hospital, Cancer Centre, Birmingham, United Kingdom 2 Wolfson Computer Laboratory, Queen Elizabeth Hospital, Birmingham, United Kingdom 3 Queen Elizabeth Hospital, Department of Endocrinology, Birmingham, United Kingdom 4 Queen Elizabeth Hospital, Department of Neurosurgery, Birmingham, United Kingdom Purpose or Objective This study aimed to evaluate the prevalence of glucocorticoid-induced adrenal insufficiency in a cohort of patients with brain and skull base tumours and to identify factors which may predict its occurrence. Material and Methods Patients with brain or skull base tumours attending for a short synacthen test (SST) at a single institution between October 2010 and January 2014 were retrospectively identified. Baseline demographics and dexamethasone exposure was scrutinised. Fisher’s Exact, Student’s t- test, Mann-Whitney and the Kendall’s tau-b were used to evaluate differences between patients who passed or failed the SST. Results Thirty-one of 51 patients with previous dexamethasone exposure failed their first SST (61%). Duration of and total exposure to dexamethasone was significantly different between pass and fail groups (p=0.001 and p=0.007 respectively). No significant relationship was demonstrated between age, gender, diagnosis or mean pituitary radiation dose and SST results. Receiver operator characteristic curves generated suggest both duration of and total exposure to dexamethasone are acceptable discriminators when predicting SST failure. These curves generate values of 78 days and 171 milligram days respectively with optimum sensitivity (i.e. ability to detect SST failures.) Conclusion These values may be used clinically to identify patients at higher risk of adrenal suppression who require empirical hydrocortisone pending formal testing of the hypothalamic-pituitary-adrenal axis.

43% of patients had extracranial disease (ED) at the time of SRS. There was no statistically significant difference in overall survival for those with or without ED; (19.2 vs 27.6 months). Commonest primary histology was breast, (34.7% of cases), with a median OS of 22.0 months. Excluding the 2 patients with Melanoma, patients whose primary tumour site was gynaecological had the best overall survival (80% at 2 years). 100% OS at 2 years for ovarian primary. In terms of LC, there was no statistically significant association between local control and BED > or < 100, total dose, extracranial disease status, pre op metastasis size > or < 3cm, or cavity volume.