SBRT boost for Cauda Equina Syndrome (CRUSSH Trial)

Spinal cord compression (SCC) is a devastating complication of advanced malignancy, and can cause significant deterioration in function and quality of life (QoL). The goal of treatment is to improve functional status and symptoms, but the optimal treatment regimen for these patients has not been thoroughly established. Many patients with SCC present with uncontrolled systemic disease and poor performance status, and are not eligible for standard surgical resection. They are generally treated with 3D conformal palliative RT (3DCRT) alone, however recent trials suggest that less than 70% of patients are ambulatory, that the re-establishment of ambulation in non-ambulatory patients is poor, and the duration of improvement is guarded with radiotherapy alone. Recently, stereotactic body radiotherapy (SBRT) used alone or after previous radiotherapy to treat spinal metastasis has demonstrated superior results in pain control, tumour response and durability. SBRT requires time for careful planning, and many patients with neurologic symptoms must be treated immediately to prevent progression. Therefore the role of SBRT is still unclear in this patient population, although it seems to be a potential alternative to surgical decompression in patient not suitable for surgery. The investigators propose a feasibility study to investigate the potential benefits of dose escalation with a sequential SBRT boost to urgent 3D CRT in the setting of SCC. This regimen will allow inoperable patients to receive urgent 3DCRT while simultaneously creating the opportunity for superior outcomes with SBRT. The investigators also aim to characterize the effect on motor function and ambulation, pain and QoL. This study could stimulate further multi-center randomized trials in this area, improve motor function and patient-reported QoL, and contribute to improving oncology care in Canada in a meaningful way.