title: Radiation-induced vertebral compression fracture following spine stereotactic radiosurgery: clinicopathological correlation.
abstract: Spine stereotactic radiosurgery (SRS) is increasingly being used to treat metastatic spinal tumors. As the experience matures, high rates of vertebral compression fracture (VCF) are being observed. What is unknown is the mechanism of action; it has been postulated but not confirmed that radiation itself is a contributing factor. This case report describes 2 patients who were treated with spine SRS who subsequently developed signal changes on MRI consistent with tumor progression and VCF; however, biopsy confirmed a diagnosis of radiation-induced necrosis in 1 patient and fibrosis in the other. Radionecrosis is a rare and serious side effect of high-dose radiation therapy and represents a diagnostic challenge, as the authors have learned from years of experience with brain SRS. These cases highlight the issues in the new era of spine SRS with respect to relying on imaging alone as a means of determining true tumor progression. In those scenarios in which it is unclear based on imaging if true tumor progression has occurred, the authors recommend biopsy to rule out radiation-induced effects within the bone prior to initiating salvage therapies.
authors.affiliation: Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Canada.
authors.forename: Ameen
authors.initials: A
authors.lastname: Al-Omair
authors.forename: Roger
authors.initials: R
authors.lastname: Smith
authors.forename: Tim-Rasmus
authors.initials: TR
authors.lastname: Kiehl
authors.forename: Louis
authors.initials: L
authors.lastname: Lao
authors.forename: Eugene
authors.initials: E
authors.lastname: Yu
authors.forename: Eric M
authors.initials: EM
authors.lastname: Massicotte
authors.forename: Julia
authors.initials: J
authors.lastname: Keith
authors.forename: Michael G
authors.initials: MG
authors.lastname: Fehlings
authors.forename: Arjun
authors.initials: A
authors.lastname: Sahgal
mesh_terms: D005260:Female; D050815:Fractures, Compression / Q000209:etiology* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000188:drug therapy / Q000473:pathology; D016634:Radiosurgery / Q000009:adverse effects* / Q000295:instrumentation; D016103:Spinal Fractures / Q000209:etiology* / Q000473:pathology; D013125:Spinal Neoplasms / Q000473:pathology / Q000601:surgery*; D016896:Treatment Outcome