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Background and Purpose: 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 and Materials: 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)., Conclusion: 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.

Purpose: Compare dose distributions of traditional versus conformal beam orientations in paranasal sinus malignancies., Materials and Methods: Maximum normal tissue doses, dose volume histograms (DVH), normal tissue complication probabilities (NTCP), and the percentage of each normal tissue receiving >80% of the average target dose (V80) were calculated., Results/conclusions: Conformal planning reduced the V80 to the optic nerves and chiasm as well as the normal tissue maximum doses to the ipsilateral and contralateral optic nerves and chiasm, and mean NTCPs.

The perfluorocarbon emulsion Oxygent improves normal tissue oxygenation. A clinical trial is planned to evaluate this effect in tumors. Polarographic oxygen electrodes were calibrated in solutions of saline +/- perflubron to assess whether Oxygent influenced probe behavior. Calibrations were linear under both conditions. There were no major differences in estimated oxygen tensions.