Work

Reirradiation With Stereotactic Body Radiation Therapy for Spinal Metastases: Planning Procedure From a High-Volume Multidisciplinary Spine Oncology Program (SOaR2)

Year: 2025

Type: article

Abstract: Purpose To develop a systematic spine reirradiation planning protocol prioritizing patient safety and maximizing tumor dose delivery. Methods Patients are presented at a multi-disciplinary Spine Oncology tumor board to confirm suspicion for recurrent or progressive malignancy and are evaluated in clinic by Radiation Oncology and Neurosurgery. Suitable patients proceed to CT/MRI simulation. A dedicated physics pathway is activated with fusion of the MRI and planning CT scan, verified independently by two physicists. The prior radiation dataset is registered to the new imaging dataset, and prior dose is displayed on the new imaging dataset. Physical dose, EQD 2 α/β=2, and EQD 2 α/β=3 plans are generated to evaluate prior dose to organs at risk (OAR). Target volumes are defined on the new dataset. Dose, fractionation, and OAR constraints are prescribed by the treating physician in accordance with the literature with priority given to respect OARs. Constraints are stipulated as EQD 2 -based objectives and converted to physical dose for the current plan. A plan-sum of the current course and all prior courses is created and displayed on the new imaging dataset for evaluation. Composite, EQD 2 α/β=2, and EQD 2 α/β=3 plans are generated to evaluate current and cumulative dose to the target and OARs. Treatment is delivered on a six-degrees-of-freedom couch with pre-, mid-, and post-treatment CBCT imaging. Registration-based shifts greater than 2 mm or 1 degree are evaluated. When requested, physicists perform quantitative analysis of dosimetric impact using a forward calculation of the plan on the planning image with the treatment shifts applied to determine if an offline plan adaptation is necessary. Results Our protocol contributes to the growing literature on spinal reirradiation with SBRT and enables safe treatment in cases of incidental spinal cord exposure. Conclusions We developed a systematic approach to planning and delivering spinal reirradiation with SBRT.

Source: Practical Radiation Oncology

DOI: 10.1016/j.prro.2025.12.002