Vertebral compression fractures after stereotactic body radiation therapy: a large, multi-institutional, multinational evaluation

Abstract

<jats:sec> <jats:title>OBJECTIVE</jats:title> <jats:p>The purpose of this study was to identify factors contributing to an increased risk for vertebral compression fracture (VCF) following stereotactic body radiation therapy (SBRT) for spinal tumors.</jats:p></jats:sec> <jats:sec> <jats:title>METHODS</jats:title> <jats:p>A total of 594 tumors were treated with spinal SBRT as primary treatment or re-irradiation at 8 different institutions as part of a multi-institutional research consortium. Patients underwent LINAC-based, image-guided SBRT to a median dose of 20 Gy (range 8–40 Gy) in a median of 1 fraction (range 1–5 fractions). Median patient age was 62 years. Seventy-one percent of tumors were osteolytic, and a preexisting vertebral compression fracture (VCF) was present in 24% of cases. Toxicity was assessed following treatment. Univariate and multivariate analyses were performed using a logistic regression method to determine parameters predictive for post-SBRT VCF.</jats:p></jats:sec> <jats:sec> <jats:title>RESULTS</jats:title> <jats:p>At a median follow-up of 10.1 months (range 0.03–57 months), 80% of patients had local tumor control. At the time of last imaging follow-up, at a median of 8.8 months after SBRT, 3% had a new VCF, and 2.7% had a progressive VCF. For development of any (new or progressive) VCF following SBRT, the following factors were predictive for VCF on univariate analysis: short interval from primary diagnosis to SBRT (less than 36.8 days), solitary metastasis, no additional bone metastases, no prior chemotherapy, preexisting VCF, no MRI used for target delineation, tumor volume of 37.3 cm<jats:sup>3</jats:sup> or larger, equivalent 2-Gy-dose (EQD<jats:sub>2</jats:sub>) tumor of 41.8 Gy or more, and EQD<jats:sub>2</jats:sub> spinal cord D<jats:sub>max</jats:sub> of 46.1 Gy or more. Preexisting VCF, solitary metastasis, and prescription dose of 38.4 Gy or more were predictive on multivariate analysis. The following factors were predictive of a new VCF on univariate analysis: solitary metastasis, no additional bone metastases, and no MRI used for target delineation. Presence of a solitary metastasis and lack of MRI for target delineation remained significant on multivariate analysis.</jats:p></jats:sec> <jats:sec> <jats:title>CONCLUSIONS</jats:title> <jats:p>A VCF following SBRT is more likely to occur following treatment for a solitary spinal metastasis, reflecting a more aggressive treatment approach in patients with adequately controlled systemic disease. Higher prescription dose and a preexisting VCF also put patients at increased risk for post-SBRT VCF. In these patients, pre-SBRT cement augmentation could be considered to decrease the risk of subsequent VCF.</jats:p></jats:sec>

Local response and pathologic fractures following stereotactic body radiotherapy versus three-dimensional conformal radiotherapy for spinal metastases - a randomized controlled trial

“…Similar rates of preexisting VCFs (24%) were detected in a large retrospective study of 594 treated spinal tumors by Jaward et al [21]. VCF rates in relevant studies varies between 7 and 39% [22–26].…”

Frequency of symptomatic vertebral body compression fractures requiring intervention following single-fraction stereotactic radiosurgery for spinal metastases

“…3,5,8,15,17,20 Median follow-up in these publications ranges from 7 to 15 months, with a median or mean time to fracture between 2 and 25 months. All studies reported an increased risk of fracture in patients with lytic metastases.…”

“…3,5,17 Individual studies have also cited increasing dose per fraction, age > 55 years, increasing vertebral body tumor involvement, thoracolumbar junction and lumbar level metastases, tumor progression, lung and/or hepatocellular histology, solitary metastases, and lack of MRI for treatment planning as risk factors for VCF. 3,5,8,15,17,20 Variability in patient selection, fracture detection, presence of tumor, follow-up, and radiation methods may account for the wide range in the reported radiographic fracture risk and time to fracture. A paucity of data relates to the symptomatology of post-SRS VCF, with most of the above-mentioned studies reporting radiographic VCF progression rather than VCF-associated symptomatology.…”

“…Radiation-associated VCF has been described in several publications and its incidence ranges from 5.7% to 39%. 3,5,8,15,17,20 Most studies have analyzed patients treated with a broad range of raAbbreviAtioNs IG-IMRT = image-guided IMRT; IMRT = intensity-modulated radiation therapy; IQR = interquartile range; KPS = Karnofsky Performance Scale; SINS = Spinal Instability Neoplastic Score; SRS = stereotactic radiosurgery; VCF = vertebral body compression fracture. obJeCtive The purpose of this study was to determine the rate of symptomatic vertebral body compression fractures (VCFs) requiring kyphoplasty or surgery in patients treated with 24-Gy single-fraction stereotactic radiosurgery (SRS).…”

Vertebral fractures following stereotactic body radiotherapy for spine metastases

“…The 15 studies identified are listed in Table 2 with the relevant findings. 10,19,20,[22][23][24][25][26][27][28][29][30][31][32][33] The majority involved patients with diverse primary tumour locations or histologies. Thibault et al focused specifically on patients with renal cell carcinoma (RCC) metastases, and Yoo et al only reported lesions from hepatocellular carcinoma (HCC) origin.…”