title: Five-Year Outcomes of High-Dose Single-Fraction Spinal Stereotactic Radiosurgery.
abstract: OBJECTIVE
  To characterize local tumor control and toxicity risk in very long-term survivors (>5 years) after high-dose spinal image guided, intensity modulated radiation therapy delivered as single-dose stereotactic radiosurgery (SRS). Previously published spinal SRS outcome analyses have included a heterogeneous population of cancer patients, mostly with short survival. This is the first study reporting the long-term tumor control and toxicity profiles after high-dose single-fraction spinal SRS.
  
  
  METHODS
  The study population included all patients treated from June 2004 to July 2009 with single-fraction spinal SRS (dose 24 Gy) who had survived at least 5 years after treatment. The endpoints examined included disease progression, surgical or radiation retreatment, in-field fracture development, and radiation-associated toxicity, scored using the Radiation Therapy Oncology Group radiation morbidity scoring criteria and the Common Terminology Criteria for Adverse Events, version 4.0. Local control and fracture development were assessed using Kaplan-Meier analysis.
  
  
  RESULTS
  Of 278 patients, 31 (11.1%), with 36 segments treated for spinal tumors, survived at least 5 years after treatment and were followed up radiographically and clinically for a median of 6.1 years (maximum 102 months). The histopathologic findings for the 5-year survivors included radiation-resistant metastases in 58%, radiation-sensitive metastases in 22%, and primary bone tumors in 19%. In this selected cohort, 3 treatment failures occurred at a median of 48.6 months, including 2 recurrences in the radiation field and 1 patient with demonstrated progression at the treatment margins. Ten lesions (27.8%) were associated with acute grade 1 cutaneous or gastrointestinal toxicity. Delayed toxicity ≥ 3 months after treatment included 8 cases (22.2%) of mild neuropathy, 2 (5.6%) of gastrointestinal discomfort, 8 (22.2%) of dermatitides, and 3 (8.3%) of myalgias/myositis. Thirteen treated levels (36.1%) in 12 patients demonstrated progressive vertebral body collapse or endplate fractures at a median of 25.7 months (range 11.6-76.0), of which 5 (14%) became symptomatic and subsequently required percutaneous cement augmentation or surgery.
  
  
  CONCLUSIONS
  In the longest-term series to date, high-dose single-fraction spinal SRS retained an excellent safety profile among long-term survivors (>5 years).
authors.affiliation: Division of Neurological Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York; Department of Neurological Surgery, Weill Cornell Medical College, New York Presbyterian Hospital, New York, New York.
authors.forename: Nelson
authors.initials: N
authors.lastname: Moussazadeh
authors.affiliation: Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York.
authors.forename: Eric
authors.initials: E
authors.lastname: Lis
authors.affiliation: Department of Radiation Oncology, New York Methodist Hospital, Brooklyn, New York.
authors.forename: Evangelia
authors.initials: E
authors.lastname: Katsoulakis
authors.affiliation: Division of Neurological Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York.
authors.forename: Sweena
authors.initials: S
authors.lastname: Kahn
authors.affiliation: Division of Neurological Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York.
authors.forename: Marek
authors.initials: M
authors.lastname: Svoboda
authors.affiliation: Division of Neurological Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York.
authors.forename: Natalie M
authors.initials: NM
authors.lastname: DiStefano
authors.affiliation: Division of Neurological Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York.
authors.forename: Lily
authors.initials: L
authors.lastname: McLaughlin
authors.affiliation: Division of Neurological Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York; Department of Neurological Surgery, Weill Cornell Medical College, New York Presbyterian Hospital, New York, New York.
authors.forename: Mark H
authors.initials: MH
authors.lastname: Bilsky
authors.affiliation: Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York.
authors.forename: Yoshiya
authors.initials: Y
authors.lastname: Yamada
authors.affiliation: Division of Neurological Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York; Department of Neurological Surgery, Weill Cornell Medical College, New York Presbyterian Hospital, New York, New York. Electronic address: lauferi@mskcc.org.
authors.forename: Ilya
authors.initials: I
authors.lastname: Laufer
mesh_terms: D000328:Adult; D000368:Aged; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D005598:Fractures, Spontaneous / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D011836:Radiation Tolerance; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods* / Q000401:mortality; D011879:Radiotherapy Dosage; D061089:Radiotherapy, Image-Guided / Q000009:adverse effects / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects / Q000379:methods; D019233:Retreatment / Q000379:methods; D012189:Retrospective Studies; D016103:Spinal Fractures / Q000209:etiology; D013125:Spinal Neoplasms / Q000556:secondary / Q000601:surgery*; D017741:Survivors; D013997:Time Factors; D017211:Treatment Failure