ESTRO 2023 - Abstract Book

S341

Sunday 14 May 2023

ESTRO 2023

Conclusion There has been significant change in consolidation approach for PCNSL with decreased utilization of WBRT plus cytarabine and increased utilization of cytarabine alone. However, RD-WBRT is associated with excellent outcomes across RPA classes. In light of preliminary data from the ongoing RTOG 1114 trial demonstrating improved PFS and no early neurotoxicity signal, RD-WBRT could be more strongly considered, particularly for higher RPA classes.

OC-0440 Long-term results from a phase 1 trial of spine SBRT in inoperable patients with cord compression

A. Ghia 1 , N. Guha-Thakurta 2 , J. Li 1 , S. Settle 3 , M. McAleer 1 , T. Briere 4 , C. Tatsui 5 , P. Brown 6 , T. Beckham 1 , C. Wang 1 , D. Yeboa 1 , E. Chang 7 , L. Rhines 5 1 University of Texas, MD Anderson Cancer Center, Radiation Oncology, Houston, USA; 2 University of Texas, MD Anderson Cancer Center, Diagnostic Radiology, Houston, USA; 3 Alaska Cyberknife Center, Radiation Oncology, Anchorage, USA; 4 University of Texas, MD Anderson Cancer Center, Radiation Physics, Houston, USA; 5 University of Texas, MD Anderson Cancer Center, Neurosurgery, Houston, USA; 6 Mayo Clinic, Radiation Oncology, Rochester, USA; 7 University of Southern California, Keck School of Medicine, Radiation Oncology, Los Angeles, USA Purpose or Objective We seek to establish the feasibility of using spine stereotactic radiosurgery (SSRS) allowing for spinal cord dose constraint relaxation as the primary management of metastatic epidural spinal cord compression (MESCC) in inoperable patients monitoring for radiation related toxicity and radiographic local control (LC). Materials and Methods Patients with MESCC in the thoracic spine deemed inoperable with no prior history of radiation at the site of interest were enrolled on this prospective Phase 1 single institution protocol (Figure 1). Single fraction SSRS was delivered to a histology dependent prescription dose of 18 or 24 Gy. Spinal cord constraint relaxation was performed from an initial allowable Dmax cohort of 10 Gy only if tumor progression occurred. If the risk of radiation induced spinal cord myelopathy (RM) remained lower than the risk of tumor progression, then the cord Dmax was elevated in 2 Gy increments to a maximum of 16 Gy in the final cohort. Patients were monitored every 3 months with follow-up visits, MRI scans and validated patient reported outcome surveys.