Advances in Radiation Oncology (Jul 2022)

Clinical Outcomes of Dose-Escalated Hypofractionated External Beam Radiation Therapy (5 Gy × 5 Fractions) for Spine Metastasis

  • Jacob Y. Shin, MD,
  • Noah J. Mathis, BS,
  • Neil Ari Wijetunga, MD, PhD,
  • Divya Yerramilli, MD,
  • Daniel S. Higginson, MD,
  • Adam M. Schmitt, MD,
  • Daniel R. Gomez, MD,
  • Yoshiya J. Yamada, MD,
  • Jonathan T. Yang, MD, PhD

Journal volume & issue
Vol. 7, no. 4
p. 100906

Abstract

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Purpose: The objective of this study was to determine the toxicities and outcomes of patients with spinal metastasis treated with external beam radiation therapy (EBRT) to 25 Gy in 5 fractions. Methods and Materials: Data were extracted from an institutional tumor registry for patients with spinal metastasis who were treated with EBRT to 25 Gy in 5 fractions to their spinal lesion(s). Cox regression and Kaplan-Meier analyses to determine local control and overall survival (OS) were employed. Results: Seventy-five patients with 86 total treated spinal metastatic tumors were identified. The median follow-up was 7 months. The median age was 66 years. Fifty-six patients (75.7%) experienced partial or complete pain relief for a median duration of 6 months (range, 1-33). Fifty-one (59.3%) cases were planned using intensity modulated radiation therapy while 19 (22.1%) employed 3-dimensional conformal radiation therapy and 16 (18.6%) cases used nonconformal radiation technique. Greater than 90% of cases had a point dose maximum to the spinal cord/cauda equina <27.5 Gy. No patient experienced treatment-related myelopathy. The most common toxicities were fatigue (23.3%), pain flare (14.0%), and nausea (8.1%). There were no grade 3 toxicities. One-year local control was 80.6%, and 1-year OS was 38.4%. Higher Karnofsky performance status (P = .001) and radiosensitive tumor histology (P = .014) were significant predictors for better OS. Conclusions: Our single-institutional retrospective analysis of patients with spinal metastasis suggested that palliative EBRT to 25 Gy in 5 fractions is safe, with a low toxicity profile and minimal risk for myelopathy with an achievable dose maximum to the spinal cord and cauda equina ≤27 Gy (equivalent total dose in 2-Gy fractions ≤50 Gy), and it may provide durable palliation and local control in cases where stereotactic body radiation therapy may not be indicated.