title: Cervix cancer oxygenation measured following external radiation therapy.
abstract: OBJECTIVE
  Tumor hypoxia may be an important factor predicting relapse following radiation therapy. This study was designed to determine the relationship between the oxygenation parameters measured using a polarographic oxygen electrode, prior to and during treatment in patients with cervix cancer, and to assess these results with regard to patient survival.
  
  
  METHODS
  Forty-three patients had pretreatment oxygen assays performed and measurements repeated following external beam radiation to a median dose of 50 Gy (range 26-52 Gy). Stage distribution showed 15 patients in Stage IB, 17 in Stage II, and 11 in Stage III. The median tumor size was 5 cm (range 3-10 cm).
  
  
  RESULTS
  The median proportion of pO2 values <5 mm Hg (the HP5) was 41% following radiation, and the median pO2 was 12 mm Hg. These results were not significantly different from the pretreatment HP5 or pO2 of 37% and 12 mm Hg, respectively. Disease-free survival at 2 years was 50% in patients with posttreatment HP5 < or =50%, compared to 60% when posttreatment HP5 was >50% (p = 0.35).
  
  
  CONCLUSIONS
  Unlike pretreatment results, tumour oxygenation measured following external radiation does not appear to be a useful predictive assay in patients with cervical cancer.
authors.affiliation: Department of Radiation Oncology, Ontario Cancer Institute/Princess Margaret Hospital, University of Toronto, Canada.
authors.forename: A W
authors.initials: AW
authors.lastname: Fyles
authors.forename: M
authors.initials: M
authors.lastname: Milosevic
authors.forename: M
authors.initials: M
authors.lastname: Pintilie
authors.forename: R P
authors.initials: RP
authors.lastname: Hill
mesh_terms: D000328:Adult; D000368:Aged; D015687:Cell Hypoxia; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008875:Middle Aged; D009367:Neoplasm Staging; D010101:Oxygen Consumption; D010313:Partial Pressure; D016896:Treatment Outcome; D002583:Uterine Cervical Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000532:radiotherapy*