ESTRO 2024 - Abstract Book

S759

Clinical - CNS

ESTRO 2024

- Tseng, CL; Chen, H; Stewart, J; et al. High-grade glioma radiation therapy on a high field 1.5 Tesla MR-Linac - workflow and initial experience with daily adapt-to-position (ATP) MR guidance: A first report. Front Oncol 12 :1060098; 2022. doi: 10.3389/fonc.2022.1060098.

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Poster Discussion

18 F-Fluciclovine PET/CT characterization of large BM treated with SSRS: phase 1 interim analysis

Alonso La Rosa 1 , Surya N. Chundru 2 , Martin C. Tom 3 , Hao V. Vuong 2 , Tugce Kutuk 1 , Sreenija Yarlagadda 1 , D Jay D. Wieczorek 1,4 , Yongsook C. Lee 1,4 , Maria Carolina Avendano 1 , Muni B. rubens 5 , Ranjini Tolakanahalli 1,4 , Michael W. McDermott 6,7 , Matthew D. Hall 1,4 , Alonso N. Gutierrez 1,4 , Manmeet S. Ahluwalia 8,7 , Minesh P. Mehta 1,4 , Rupesh Kotecha 1,4,7 1 Miami Cancer Insititute. Baptist Health South Florida, Radiation Oncology, Miami, USA. 2 Miami Cancer Insititute. Baptist Health South Florida, Diagnostic Radiology, Miami, USA. 3 The University of Texas MD Anderson Cancer Center, Radiation Oncology, Texas, USA. 4 Herbert Wertheim College of Medicine, Florida International University, Radiation Oncology, Miami, USA. 5 Miami Cancer Insititute. Baptist Health South Florida, Statistics, Miami, USA. 6 Miami Cancer Insititute. Baptist Health South Florida, Neurosurgery, Miami, USA. 7 Herbert Wertheim College of Medicine, Florida International University, Translational Medicine, Miami, USA. 8 Miami Cancer Insititute. Baptist Health South Florida, Medical Oncology, Miami, USA Temporally staged stereotactic radiosurgery (SSRS), the delivery of SRS in two to three sessions over a span of 2-4 weeks, has been used for large brain metastasis to improve tumor control rates with acceptable toxicities, compared to traditional single session SRS. PET/CT using 18F-Fluciclovine, an amino acid radiotracer, has uptake in untreated brain metastases and has demonstrated initial diagnostic value in differentiating recurrent disease from treatment-related changes. Therefore, the integration of temporally staged SRS and 18F-Fluciclovine PET/CT represents a potential avenue to evaluate the development of an imaging biomarker to assess response to radiotherapy. We present interim findings from a phase 1 proof-of-concept study (NCT04689048) aimed at evaluating the potential clinical relevance of the amino acid radiotracer 18F-fluciclovine PET/CT as a functional integral biomarker for patients undergoing SSRS for large brain metastases. Purpose/Objective:

Material/Methods:

Patients who presented with previously untreated large brain metastases (≥1 lesion; >2cm in maximal diameter) underwent three 18F-Fluciclovine PET/CT and MRI imaging assessments immediately prior to initial SSRS (15 Gy), immediately prior to second SSRS (15 Gy), and at first follow-up 8 weeks post-second SSRS. This interim analysis focused on the imaging features derived from static PET images encompassing data from the first thirteen enrolled patients. Eleven patients (n=11; 13 tumors) completed baseline imaging, nine (n=9; 11 tumors) completed SSRS