title: Hypoxic prostate/muscle PO2 ratio predicts for outcome in patients with localized prostate cancer: long-term results.
abstract: OBJECTIVE
  To correlate tumor oxygenation status with long-term biochemical outcome after prostate brachytherapy.
  
  
  METHODS
  Custom-made Eppendorf PO(2) microelectrodes were used to obtain PO(2) measurements from the prostate (P), focused on positive biopsy locations, and normal muscle tissue (M), as a control. A total of 11,516 measurements were obtained in 57 men with localized prostate cancer immediately before prostate brachytherapy was given. The Eppendorf histograms provided the median PO(2), mean PO(2), and % <5 mm Hg or <10 mm Hg. Biochemical failure (BF) was defined using both the former American Society of Therapeutic Radiation Oncology (ASTRO) (three consecutive raises) and the current Phoenix (prostate-specific antigen nadir + 2 ng/mL) definitions. A Cox proportional hazards regression model evaluated the influence of hypoxia using the P/M mean PO(2) ratio on BF.
  
  
  RESULTS
  With a median follow-up time of 8 years, 12 men had ASTRO BF and 8 had Phoenix BF. On multivariate analysis, P/M PO(2) ratio <0.10 emerged as the only significant predictor of ASTRO BF (p = 0.043). Hormonal therapy (p = 0.015) and P/M PO(2) ratio <0.10 (p = 0.046) emerged as the only independent predictors of the Phoenix BF. Kaplan-Meier freedom from BF for P/M ratio <0.10 vs. ≥0.10 at 8 years for ASTRO BF was 46% vs. 78% (p = 0.03) and for the Phoenix BF was 66% vs. 83% (p = 0.02).
  
  
  CONCLUSIONS
  Hypoxia in prostate cancer (low mean P/M PO(2) ratio) significantly predicts for poor long-term biochemical outcome, suggesting that novel hypoxic strategies should be investigated.
authors: Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA 19111, USA.
authors: Aruna
authors: A
authors: Turaka
authors: Mark K
authors: MK
authors: Buyyounouski
authors: Alexandra L
authors: AL
authors: Hanlon
authors: Eric M
authors: EM
authors: Horwitz
authors: Richard E
authors: RE
authors: Greenberg
authors: Benjamin
authors: B
authors: Movsas
mesh_terms: D000368:Aged; D001918:Brachytherapy; D015687:Cell Hypoxia; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D008839:Microelectrodes; D008875:Middle Aged; D015999:Multivariate Analysis; D018482:Muscle, Skeletal / Q000378:metabolism*; D009364:Neoplasm Recurrence, Local / Q000097:blood; D009367:Neoplasm Staging; D010100:Oxygen / Q000378:metabolism*; D010313:Partial Pressure; D016016:Proportional Hazards Models; D011467:Prostate / Q000378:metabolism*; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000532:radiotherapy*; D011880:Radiotherapy Planning, Computer-Assisted
chemical_list: D007457:Iodine Radioisotopes; D017430:Prostate-Specific Antigen; D010100:Oxygen