title: Frequency of symptomatic vertebral body compression fractures requiring intervention following single-fraction stereotactic radiosurgery for spinal metastases.
abstract: 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). METHODS This retrospective analysis included all patients who had been treated with 24-Gy, single-fraction, image-guided intensity-modulated radiation therapy for histologically confirmed solid tumor metastases over an 8-year period (2005-2013) at Memorial Sloan Kettering Cancer Center. Charts and imaging studies were reviewed for post-SRS kyphoplasty or surgery for mechanical instability. A Spinal Instability Neoplastic Score (SINS) was calculated for each patient both at the time of SRS and at the time of intervention for VCF. RESULTS Three hundred twenty-three patients who had undergone single-fraction SRS between C-1 and L-5 were included in this analysis. The cumulative incidence of VCF 5 years after SRS was 7.2% (95% CI 4.1-10.2), whereas that of death following SRS at the same time point was 82.5% (95% CI 77.5-87.4). Twenty-six patients with 36 SRS-treated levels progressed to symptomatic VCF requiring treatment with kyphoplasty (6 patients), surgery (10 patients), or both (10 patients). The median time to symptomatic VCF was 13 months. Seven patients developed VCF at 11 levels adjacent to the SRS-treated level. Fractured levels had no evidence of tumor progression. The median SINS changed from 6.5 at SRS (interquartile range [IQR] 4.3-8.8) to 11.5 at stabilization (IQR 9-13). In patients without prior stabilization at the level of SRS, there was an association between the SINS and the time to fracture. CONCLUSIONS Five years after ablative single-fraction SRS to spinal lesions, the cumulative incidence of symptomatic VCF at the treated level without tumor recurrence was 7.2%. Higher SINSs at the time of SRS correlated with earlier fractures.
authors.affiliation: Departments of1Neurological Surgery.|2Department of Neurological Surgery, Weill Cornell Medical College, NewYork-Presbyterian Hospital, New York, New York; and.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Virk
authors.affiliation: 3Radiation Oncology.
authors.forename: James E
authors.initials: JE
authors.lastname: Han
authors.affiliation: 4Epidemiology and Biostatistics, and.
authors.forename: Anne S
authors.initials: AS
authors.lastname: Reiner
authors.affiliation: Departments of1Neurological Surgery.
authors.forename: Lily A
authors.initials: LA
authors.lastname: McLaughlin
authors.affiliation: 5Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Sciubba
authors.affiliation: 6Radiology, Memorial Sloan Kettering Cancer Center.
authors.forename: Eric
authors.initials: E
authors.lastname: Lis
authors.affiliation: 3Radiation Oncology.
authors.forename: Yoshiya
authors.initials: Y
authors.lastname: Yamada
authors.affiliation: Departments of1Neurological Surgery.|2Department of Neurological Surgery, Weill Cornell Medical College, NewYork-Presbyterian Hospital, New York, New York; and.
authors.forename: Mark
authors.initials: M
authors.lastname: Bilsky
authors.affiliation: Departments of1Neurological Surgery.|2Department of Neurological Surgery, Weill Cornell Medical College, NewYork-Presbyterian Hospital, New York, New York; and.
authors.forename: Ilya
authors.initials: I
authors.lastname: Laufer
mesh_terms: D000368:Aged; D005260:Female; D050815:Fractures, Compression / Q000209:etiology* / Q000601:surgery*; D006801:Humans; D017567:Karnofsky Performance Status; D058498:Kyphoplasty / Q000379:methods*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging / Q000601:surgery; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000601:surgery*; D016634:Radiosurgery / Q000009:adverse effects*; D013125:Spinal Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary / Q000601:surgery; D015898:Tomography Scanners, X-Ray Computed
keywords: 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; complications; kyphoplasty; stereotactic radiosurgery; vertebral body fracture