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Chapter Summary
• Context: Radiotherapy occupies a central position in the contemporary management of spinal tumors, both in pain palliation and local control of metastases and select primary neoplasms. Technological advancements have profoundly transformed its ability to treat lesions adjacent to the spinal cord. Two-dimensional techniques have yielded to three-dimensional planning, intensity-modulated beam delivery, and image-guided radiotherapy, enabling the use of Stereotactic Body Radiation Therapy (SBRT) in carefully selected patients. However, higher precision does not eliminate the need to evaluate mechanical stability, epidural extension, oncological prognosis, and toxicity risks. This chapter integrates SINS, Tokuhashi score, and the Bilsky classification into radiation planning, demonstrating the progressive evolution of dose conformity and neural sparing in Figures 57.3 through 57.6. Artificial intelligence, proton therapy, and intraosseous radiotherapy are presented as emerging avenues for expanding therapeutic personalization.
• Chapter Objective: Understand the indications and limitations of radiotherapy in vertebral tumors, differentiate conventional from advanced modalities, and recognize the role of SBRT. The chapter also integrates mechanical stability, epidural compression, and prognosis into radiation decision-making, discusses complications, and presents emerging planning and delivery technologies.
• Radiotherapy as part of an integrated strategyThe presence of a tumor in the spine does not, in isolation, indicate a specific radiation modality. Histological type, extent, stability, neural compromise, prior treatments, and clinical objectives must be known. SINS, Tokuhashi, and Bilsky address different questions. Table 57.1 addresses stability; Table 57.2, prognosis; and Table 57.3, the degree of epidural compression. Used together, they help avoid treating only the tumor imaging without considering its mechanical and neurological repercussions.
• Imaging and planningMRI is essential for delineating tumor extension and neural involvement. CT provides detailed bony information and directly participates in radiation treatment planning. PET-CT adds systemic and metabolic staging. Table 57.4 summarizes the advantages and limitations of these modalities.
• Technological evolution of radiotherapyConventional radiotherapy exhibits lower ability to conform dose around critical structures. 3D conformal radiotherapy introduced CT-based planning. Intensity-Modulated Radiation Therapy (IMRT) expanded the capacity to modulate dose distribution, while Image-Guided Radiation Therapy (IGRT) allows real-time verification and positional correction. SBRT combines high precision and ablative doses delivered in a small number of fractions. Its delivery requires rigid immobilization, rigorous planning, and strict adherence to spinal cord tolerance limits.
• Tumor control versus spinal mechanicsRadiotherapy can produce excellent tumor control, but it does not correct an unstable spine. Mechanical evaluation must precede radiation when there is vertebral collapse, deformity, or load-bearing pain. Likewise, high-grade epidural compression may require separation surgery prior to radiotherapy.
• ToxicityRadiation myelopathy, post-radiation vertebral compression fracture, and transient pain flare are among the discussed complications. Table 57.5 presents the technical dose-volume constraints utilized in SBRT planning.
• New perspectivesArtificial intelligence applied to contouring and risk prediction, proton therapy, combination with immunotherapy, and intraosseous radiotherapy represent evolving technologies. Figures 57.7 and 57.8 illustrate an intraosseous radiation delivery strategy combined with percutaneous vertebral augmentation.
• Clinical Application: Before referring a patient directly for radiotherapy, one must determine whether the primary threat is oncological, mechanical, or neurological. A painful lesion in a stable spine represents a vastly different scenario from a metastasis with progressive deformity or high-grade epidural compression. SINS identifies patients requiring surgical stabilization. Bilsky characterizes epidural tumor relationship to neural structures. Prognosis and systemic status determine the appropriate intensity of treatment. Selecting between conventional palliative radiation and SBRT must not depend solely on machine availability. Histology, local control goals, prior irradiation, fracture risk, and cord proximity must be evaluated. In follow-up, worsening pain after radiation must be critically assessed: it may represent transient flare, tumor progression, or a radiation-induced fracture.
