title: Oxygenation of head and neck cancer: changes during radiotherapy and impact on treatment outcome.
abstract: OBJECTIVE
  To evaluate the long term clinical significance of tumor oxygenation in a population of head and neck cancer patients receiving radiotherapy and to assess changes in tumor oxygenation during the course of treatment.
  
  
  METHODS
  Patients with head and neck cancer receiving primary RT underwent pretreatment polarographic tumor oxygen measurement of the primary site or a metastatic neck lymph node. Treatment consisted of once daily (2 Gy/fraction to a total dose of 66-70 Gy) or twice daily irradiation (1.25 Gy/fraction to 70-75 Gy) to the primary site. Twenty-seven patients underwent a second series of measurements early in the course of irradiation.
  
  
  RESULTS
  Sixty-three patients underwent pretreatment tumor oxygen assessment (primary site, n = 24; nodes, n = 39). The median pO2 for primary lesions was 4.8 mmHg, and it was 4.3 mmHg for cervical nodes. There was a weak association between anemia and more poorly oxygened tumors, but many non-anemic patients still had poorly oxygenated tumors. Repeat assessments of tumor oxygenation after 10-15 Gy were unchanged compared to pretreatment baselines. Poorly oxygenated nodes pretreatment were more likely to contain viable residual disease at post-radiation neck dissection. Median follow-up time for surviving patients was 20 months (range 3-50 months). Hypoxia (tumor median pO2 <10 mmHg) adversely affected 2 year local-regional control (30 vs. 73%, P = 0.01), disease-free survival (26 vs. 73%, P = 0.005), and survival (35 vs. 83%, P = 0.02).
  
  
  CONCLUSIONS
  Tumor oxygenation affects the prognosis of head and neck cancer independently of other known prognostic variables. This parameter may be a useful tool for the selection of patients for investigational treatment strategies.
authors.affiliation: Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: Brizel
authors.forename: R K
authors.initials: RK
authors.lastname: Dodge
authors.forename: R W
authors.initials: RW
authors.lastname: Clough
authors.forename: M W
authors.initials: MW
authors.lastname: Dewhirst
mesh_terms: D000740:Anemia / Q000150:complications; D002294:Carcinoma, Squamous Cell / Q000150:complications / Q000378:metabolism* / Q000401:mortality / Q000532:radiotherapy*; D018572:Disease-Free Survival; D006801:Humans; D008207:Lymphatic Metastasis; D009364:Neoplasm Recurrence, Local; D010039:Otorhinolaryngologic Neoplasms / Q000150:complications / Q000378:metabolism* / Q000401:mortality / Q000532:radiotherapy*; D010100:Oxygen / Q000032:analysis*; D011048:Polarography; D015996:Survival Rate
chemical_list: D010100:Oxygen