title: Iodine-125 brachytherapy as upfront and salvage treatment for brain metastases : A comparative analysis.
abstract: BACKGROUND
  Outcome and toxicity profiles of salvage stereotactic ablative radiation strategies for recurrent pre-irradiated brain metastases are poorly defined. This study compared risk-benefit profiles of upfront and salvage iodine-125 brachytherapy (SBT) for small brain metastases. As the applied SBT treatment algorithm required histologic proof of metastatic brain disease in all patients, we additionally aimed to elucidate the value of biopsy before SBT.
  
  
  METHODS
  Patients with small untreated (n = 20) or pre-irradiated (n =28) suspected metastases intended for upfront or salvage SBT, respectively, were consecutively included. Temporary iodine-125 implants were used (median reference dose: 50 Gy, median dose rate: 15 cGy/h). Cumulative biologically effective doses (BED) were calculated and used for risk assessment. Treatment toxicity was classified according to Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer (RTOG/EORTC) criteria.
  
  
  RESULTS
  Upfront SBT was initiated in 20 patients and salvage SBT in 23. In 5 patients, salvage SBT was withheld because of proven radiation-induced lesions. Treatment groups exhibited similar epidemiologic data except for tumor size (which was slightly smaller in the salvage group). One-year local/distant tumor control rates after upfront and salvage SBT were similar (94 %/65 % vs. 87 %/57 %, p = 0.45, respectively). Grade I/II toxicity was suffered by 2 patients after salvage SBT (cumulative BED: 192.1 Gy3and 249.6 Gy3). No toxicity-related risk factors were identified.
  
  
  CONCLUSIONS
  SBT combines diagnostic yield with effective treatment in selected patients. The low toxicity rate in the salvage group points to protective radiobiologic characteristics of continuous low-dose rate irradiation. Upfront and salvage SBT are similarly effective and safe. Histologic reevaluation should be reconsidered after previous radiotherapy to avoid under- or overtreatment.
authors.affiliation: Department of Neurosurgery, Ludwig-Maximilians-University, Marchioninistr. 15, 81377, Munich, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Romagna
authors.affiliation: Department of Neurosurgery, Ludwig-Maximilians-University, Marchioninistr. 15, 81377, Munich, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Schwartz
authors.affiliation: Center for Neuropathology and Prion Research, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Rupert
authors.initials: R
authors.lastname: Egensperger
authors.affiliation: Department of Radiation-Oncology, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Juliana
authors.initials: J
authors.lastname: Watson
authors.affiliation: Department of Neurosurgery, Ludwig-Maximilians-University, Marchioninistr. 15, 81377, Munich, Germany.
authors.forename: Jörg-Christian
authors.initials: JC
authors.lastname: Tonn
authors.affiliation: Department of Radiation-Oncology, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Claus
authors.initials: C
authors.lastname: Belka
authors.affiliation: Department of Neurosurgery, Ludwig-Maximilians-University, Marchioninistr. 15, 81377, Munich, Germany. Friedrich-Wilhelm.Kreth@med.uni-muenchen.de.
authors.forename: Friedrich-Wilhelm
authors.initials: FW
authors.lastname: Kreth
authors.affiliation: Department of Radiation-Oncology, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Silke Birgit
authors.initials: SB
authors.lastname: Nachbichler
mesh_terms: D001918:Brachytherapy / Q000009:adverse effects*; D001930:Brain Injuries / Q000209:etiology / Q000517:prevention & control*; D001932:Brain Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000556:secondary*; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000009:adverse effects / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D058958:Organs at Risk / Q000528:radiation effects; D011832:Radiation Injuries / Q000209:etiology / Q000517:prevention & control*; D019275:Radiopharmaceuticals / Q000009:adverse effects / Q000627:therapeutic use; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D018714:Radiotherapy, Adjuvant; D012189:Retrospective Studies; D016879:Salvage Therapy / Q000009:adverse effects / Q000379:methods; D016896:Treatment Outcome
chemical_list: D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals
keywords: Biopsy; Molecular imaging; Neoplasms, radiation-induced; Radiotherapy; Toxicity