Postoperative Stereotactic Body Radiotherapy for Spinal Metastasis and Predictors of Local Control

Abstract

BACKGROUND Spine surgery is indicated for select patients with mechanical instability, pain, and/or malignant epidural spinal cord compression, with or without neurological compromise. Stereotactic body radiotherapy (SBRT) is an option for durable local control (LC) for metastatic spine disease. OBJECTIVE To determine factors associated with LC and progression-free survival (PFS) for patients receiving postoperative stereotactic spine radiosurgery. METHODS We analyzed consecutive patients from 2013 to 2019 treated with surgical intervention followed by SBRT. Surgical interventions included laminectomy and vertebrectomy. SBRT included patients treated with 1 to 5 fractions of radiosurgery. We analyzed LC, PFS, overall survival (OS), and toxicity. Univariate and multivariate analyses were performed. RESULTS A total of 63 patients were treated with a median follow-up of 12.5 mo. Approximately 75% of patients underwent vertebrectomy and 25% underwent laminectomy. One-year cumulative incidence of local failure was 19%. LC was significantly improved for patients receiving radiosurgery ≤40 d from surgery compared to that for patients receiving radiosurgery ≥40 d from surgery, 94% vs 75%, respectively, at 1 yr (P = .03). Patients who received preoperative embolization had improved LC with 1-yr LC of 88% vs 76% for those who did not receive preoperative embolization (P = .037). Significant predictors for LC on multivariate analysis were time from surgery to radiosurgery, higher radiotherapy dose, and preoperative embolization. The 1-yr PFS and OS was 56% and 60%, respectively. CONCLUSION Postoperative radiosurgery has excellent and durable LC for spine metastasis. An important consideration when planning postoperative radiosurgery is minimizing delay from surgery to radiosurgery. Preoperative embolization and higher radiotherapy dose were associated with improved LC warranting further study.

Clinical evaluation of vertebral body replacement of carbon fiber–reinforced polyetheretherketone in patients with tumor manifestation of the thoracic and lumbar spine

“…Adjuvant stereotactic radiotherapy is necessary to provide durable local control and was performed in 60% of patients in this study [ 1 , 18 ]. This requires minimal to no interference with radiotherapy (RT) planning as well as RT delivery, especially in the case of newer modalities such as proton beams, where these issues have a major impact [ 17 ].…”

Feasibility, safety, and efficacy of circumferential spine stereotactic body radiotherapy

“…LF in patients with circumferential epidural disease can be particularly morbid due to the risk of cord compromise. Thus, if circumferential SBRT offers the ability to safely deliver a higher BED to tumor through more precise treatment planning and delivery, it may be critical to improving LC and decreasing the morbidity associated with recurrent disease ( 5 ). This issue will likely become increasingly important moving forward.…”

“…Conventional external beam RT has traditionally been considered the standard of care for patients receiving palliative RT ( 3 ). However, the biologically effective dose (BED) delivered by conventional RT can be ineffective in some cases—particularly for patients with radioresistant histologies ( 4 , 5 ).…”

Implementation of triggered kilovoltage imaging for stereotactic radiotherapy of the spine for patients with spinal fixation hardware

“…Spinal metastasis occurs in 40–70 % of cancer patients where progression can lead to mechanical instability, cord compression, or functional compromise [1] , [2] , [3] , [4] , [5] . Surgery and radiation therapy are often used when indications such as instability or cord compression are present, with the combination of the two treatment approaches enhancing the overall quality of life for patients [6] .…”