A Volumetric Dosimetry Analysis of Vertebral Body Fracture Risk after Single Fraction Spine Stereotactic Body Radiotherapy

Definitive single fraction spine stereotactic radiosurgery for metastatic sarcoma: Simultaneous integrated boost is associated with high tumor control and low vertebral fracture risk

INTRODUCTION

Sarcoma spinal metastases (SSM) are particularly difficult to manage given their poor response rates to chemotherapy and inherent radioresistance. We evaluated outcomes in a cohort of patients with SSM uniformly treated using single-fraction simultaneous-integrated-boost (SIB) spine stereotactic radiosurgery (SSRS).

MATERIALS AND METHODS

A retrospective review was conducted at a single tertiary institution treated with SSRS for SSM between April 2007-April 2023. 16-24 Gy was delivered to the GTV and 16 Gy uniformly to the CTV. Kaplan-Meier analysis was conducted to assess time to progression of disease (PD) with proportionate hazards modelling used to determine hazard ratios (HR) and respective 95 % confidence intervals (CI).

RESULTS

70 patients with 100 lesions underwent SSRS for SSM. Median follow-up was 19.3 months (IQR 7.7-27.8). Median age was 55 years (IQR42-63). Median GTV and CTVs were 14.5 cm3 (IQR 5-32) and 52.7 cm3 (IQR 29.5-87.5) respectively. Median GTV prescription dose and biologically equivalent dose (BED) [α/β = 10] was 24 Gy and 81.6 Gy respectively. 85 lesions received 24 Gy to the GTV. 27 % of patients had Bilsky 1b or greater disease. 16 of 100 lesions recurred representing a crude local failure rate of 16 % with a median time to failure of 10.4 months (IQR 5.7-18) in cases which failed locally. 1-year actuarial local control (LC) was 89 %. Median overall survival (OS) was 15.3 months (IQR 7.7-25) from SSRS. Every 1 Gy increase in GTV absolute minimum dose (DMin) across the range (5.8-25 Gy) was associated with a reduced risk of local failure (HR = 0.871 [95 % CI 0.782-0.97], p = 0.009). 9 % of patients developed vertebral compression fractures at a median of 13 months post SSRS (IQR 7-25).

CONCLUSION

This study represents one of the most homogenously treated and the largest cohorts of patients with SSM treated with single-fraction SSRS. Despite inherent radioresistance, SSRS confers durable and high rates of local control in SSM without unexpected long-term toxicity rates.

Spine Patient Optimal Radiosurgery Treatment for Symptomatic Metastatic Neoplasms (SPORTSMEN): a randomized phase II study protocol

Background

Approximately 40% of patients with metastatic cancer will have spinal metastatic disease. Historically treated with external beam radiation therapy (EBRT) with limited durability in pain control, the increased lifespan of this patient population has necessitated more durable treatment results via spine radiosurgery/stereotactic body radiation therapy (SBRT). The goal of this study is to assess three-month pain freedom rates via the Spine Patient Optimal Radiosurgery Treatment for Symptomatic Metastatic Neoplasms (SPORTSMEN) randomized trial.

Materials and methods

This study is a prospective randomized three-arm phase II trial which will recruit patients with symptomatic spine metastases. All patients will be randomized to standard-of care SBRT (24 Gy in 2 fractions), single-fraction SBRT (19 Gy in 1 fraction), or EBRT (8 Gy in 1 fraction), with the primary endpoint of three-month pain freedom (using the Brief Pain Inventory). We expect that SPORTSMEN will help definitively answer the efficacy of spine SBRT versus EBRT for achieving pain freedom, while defining the safety and efficacy of 19 Gy single-fraction spine SBRT. Local control will be defined according to Spine Response Assessment in Neuro-Oncology (SPINO) criteria.

Discussion

This is the first phase II trial to objectively assess optimal spine SBRT dosing in the treatment of symptomatic spine metastatic disease, while assessing spine SBRT versus EBRT. Findings should allow for better determination of the efficacy of two-fraction spine SBRT versus EBRT in the United States, as well as for the novel single-fraction 19 Gy spine SBRT regimen in patients with symptomatic spine metastases.

Trial Registration

Clinicaltrials.gov identifier: NCT05617716 (registration date: November 14, 2022).

Stereotactic Body Radiation Therapy for Spinal Metastases: Benefits and Limitations

Progress in biological cancer characterization, targeted systemic therapies and multimodality treatment strategies have shifted the goals of radiotherapy for spinal metastases from short-term palliation to long-term symptom control and prevention of compilations. This article gives an overview of the spine stereotactic body radiotherapy (SBRT) methodology and clinical results of SBRT in cancer patients with painful vertebral metastases, metastatic spinal cord compression, oligometastatic disease and in a reirradiation situation. Outcomes after dose-intensified SBRT are compared with results of conventional radiotherapy and patient selection criteria will be discussed. Though rates of severe toxicity after spinal SBRT are low, strategies to minimize the risk of vertebral compression fracture, radiation induced myelopathy, plexopathy and myositis are summarized, to optimize the use of SBRT in multidisciplinary management of vertebral metastases.

Precision pain management in interventional radiology

Pain is a common manifestation of several benign and malignant conditions. Inadequate response to conservative therapies is often succeeded by incremental use of analgesics and opioids; however, such an approach is often ineffective, not well tolerated by patients, and carries the risk of addiction leading to the opioid crisis. Implementing minimally invasive percutaneous procedures, performed by interventional radiologists has proven to be successful in providing safe, effective, and patient-specific therapies across a wide range of painful conditions. In the present narrative review, we will review the repertoire of minimally invasive imaging guided interventions, which have been successfully used to treat common painful benign and malignant conditions. We briefly describe each technique, common indications, and expected results.