title: Safety and feasibility of image-guided robotic radiosurgery for patients with limited bone metastases of prostate cancer.
abstract: OBJECTIVE
  To determine the safety and feasibility after image-guided single fraction robotic stereotactic radiosurgery (SRS) in patients with bone metastases of prostate cancer.
  
  
  METHODS
  Forty patients with 64 bone metastases of prostate cancer were prospectively enrolled in a single center study and underwent 54 consecutive outpatient single session SRS procedures during a 4-year period. F-18 choline PET/CT in addition to standard CT imaging was done prior to SRS in all patients. Nineteen patients were under anti-androgen therapy, 8 patients had undergone chemotherapy before SRS. Overall survival and freedom from local tumor recurrence was analyzed with the Kaplan-Meier method.
  
  
  RESULTS
  Mean follow-up was 14 months (3-48 months). Seventy-five percent of patients had a single bone metastasis. The median tumor volume was 13 cc. The mean prescribed tumor dose was 20.2 Gy (16.5-22 Gy). Eight patients had died at the time point of the data analysis. The actuarial 6-months, 12-months, and 24-months local tumor control rate was 95.5% (95% CI: 83.0-98.8) as measured by MRI and PET CT imaging. The median initial PSA before SRS was 5.4 ng/dl (CI: 1.4-8.2) and dropped to 2.7 ng/dl (CI: 0.14-10) after 3 months. One case of progressive neurological deficits was documented.
  
  
  CONCLUSIONS
  This first report on single session, image-guided robotic SRS documents a safe, feasible, and patient-friendly treatment option in selected patients with bone metastases of prostate cancer.
authors.affiliation: Cyberknife Center Munich Grosshadern, Munich, Germany. alexander.muacevic@cyber-knife.net
authors.forename: Alexander
authors.initials: A
authors.lastname: Muacevic
authors.forename: Markus
authors.initials: M
authors.lastname: Kufeld
authors.forename: Carsten
authors.initials: C
authors.lastname: Rist
authors.forename: Berndt
authors.initials: B
authors.lastname: Wowra
authors.forename: Christian
authors.initials: C
authors.lastname: Stief
authors.forename: Michael
authors.initials: M
authors.lastname: Staehler
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000401:mortality / Q000556:secondary / Q000601:surgery*; D002794:Choline / Q000031:analogs & derivatives; D005240:Feasibility Studies; D005462:Fluorine Radioisotopes; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D011379:Prognosis; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D016634:Radiosurgery; D025321:Surgery, Computer-Assisted; D015996:Survival Rate; D014057:Tomography, X-Ray Computed
chemical_list: D005462:Fluorine Radioisotopes; D017430:Prostate-Specific Antigen; D002794:Choline