title: Spinal radiosurgery--efficacy and safety after prior conventional radiotherapy.
abstract: BACKGROUND
  Conventional external beam radiotherapy is a standard procedure for treatment of spinal metastases. In case of progression spinal cord tolerance limits further radiotherapy in pre-irradiated areas. Spinal stereotactic radiotherapy is a non-invasive option to re-treat pre-irradiated patients. Nevertheless, spinal radiosurgery results in relevant dose deposition within the myelon with potential toxicity. Aim of the study was to retrospectively analyse the efficacy and feasibility for salvage radiosurgery of spinal metastases.
  
  
  METHODS
  During a period of 4 years (2005-2009) 70 lesions in 54 patients were treated in 60 radiosurgery sessions and retrospectively analysed. Clinical (pain, sensory and motor deficit) and radiological (CT/MRI) follow-up data were collected prospectively after radiosurgery. Pain - as main symptom - was classified by the Visual Analogue Scale (VAS) score. Every patient received single session radiosurgery after having been treated first-line with conventionally fractionated radiotherapy. Kaplan-Meier method and life tables were used to analyse freedom from local failure and overall survival.
  
  
  RESULTS
  At a median follow-up of 14.5 months the actuarial rates of freedom from local failure at 6/12/18 months were 93%, 88% and 85%, respectively. The median radiosurgery dose was 1 × 18 Gy (range 10-28 Gy) to the median 70% isodose. The VAS score of patients with pain (median 6) dropped significantly (median 4, p = 0.002). In 6 out of 7 patients worse sensory or motor deficit after SRS was caused by local or distant failures (diagnosed by CT/MRI). One patient with metastatic renal cell carcinoma developed a progressive complete paraparesis one year after the last treatment at lumbar level L3. Due to multiple surgery and radiosurgery treatments at the lumbar region and further local progression, the exact reason remained unclear. Apart from that, no CTC grade III or higher toxicity has been observed.
  
  
  CONCLUSIONS
  By applying spinal radiosurgery relevant radiation doses can be limited to small parts of the myelon. This prevents myelopathic side effects and makes it an effective and safe treatment option for well-suited patients. Especially for previously irradiated patients with local failure or pain salvage SRS represents a valuable treatment option with high local control rates, low toxicity and significant pain reduction.
authors.affiliation: Department of Radiation Oncology, Ludwig-Maximilians-University, Campus Grosshadern, Marchioninistr, 15, 81377 München, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Nikolajek
authors.forename: Markus
authors.initials: M
authors.lastname: Kufeld
authors.forename: Alexander
authors.initials: A
authors.lastname: Muacevic
authors.forename: Berndt
authors.initials: B
authors.lastname: Wowra
authors.forename: Maximilian
authors.initials: M
authors.lastname: Niyazi
authors.forename: Ute
authors.initials: U
authors.lastname: Ganswindt
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology / Q000601:surgery; D010147:Pain Measurement; D016634:Radiosurgery; D011878:Radiotherapy; D012189:Retrospective Studies; D016879:Salvage Therapy / Q000379:methods; D013120:Spinal Cord Neoplasms / Q000401:mortality / Q000556:secondary / Q000601:surgery; D013125:Spinal Neoplasms / Q000401:mortality / Q000556:secondary* / Q000601:surgery*; D055815:Young Adult