Radiotherapy for spinal metastasis: A narrative review

Abstract

Despite the rapid evolution of systemic therapies and significant advances in surgical techniques, radiation therapy by itself or as an adjuvant to surgery remains the modality of choice for local control of spinal metastasis. Radiation can be used with an ablative intent for lasting local control of spinal metastasis or with a palliative intent to ameliorate pain, prevent pathological fractures, and relieve epidural spinal cord compression. This article aims to review the various modalities of radiotherapy. The lack of precision with conventional external beam radiotherapy (cEBRT) poses a significant radiation hazard to vital structures adjacent to the spine. This necessitates lowering of the radiation dosage, which may not be adequate to treat certain resistant tumors. Currently, the use of cEBRT is recommended for radiosensitive histologies only. Stereotactic body radiotherapy (SBRT) allows tumoricidal doses of radiation to be safely delivered to the tumor tissue. SBRT has been shown to provide durable local control, even for spine metastasis from tumors with radioresistant histologies. SBRT can also be offered as a reirradiation technique for tumor progression following a course of cEBRT. Currently, SBRT alone is recommended for radioresistant spinal metastasis limited to 1–2 spinal segments, with limited paraspinal spread and mild-to-moderate spinal cord compression in a stable spine. Charged particle therapy is useful for resistant histologies and further reduces the dose to normal structures within the vicinity of the tumor.