Normobaric oxygen as a sensitizer in radiotherapy for advanced head and neck cancer

The aim of this study was to evaluate radiosensitizing effect of normobaric oxygen breathing in radiotherapy for advanced head and neck cancers. Forty seven patients with advanced squamous cell carcinomas of the head and neck (7% in Stage III and 93% in Stage IV) were entered in the study. Breathing the pure, normobaric oxygen was given for 15-20 min in the treatment room. Irradiation started immediately after oxygen breathing. Conventional, megavoltage radiotherapy to the total doses in the range of 46-67.5 Gy was used. The control group was 46 patients with the same diagnosis and stage treated by radiotherapy alone. Locoregional tumor control was 36% in the study group compared to 15% in the control (p < 0.05). Mean survival time was 15.8 and 11.8 months, and 3-year survival was 19% and 2%, respectively (p < 0.05). Survival depended on total tumor dose and total nodal dose. No significant influence of the tumor location on local control and importance of the size of dose per fraction and overall treatment time were found. The most common failure in both groups was persistent tumor. Mean recurrence time was 5 months in the study group and 8 months in the control. Present results suggest that the use of normobaric oxygen breathing prior to irradiation could increase effectiveness of conventional radiotherapy for advanced squamous cell carcinomas of head and neck.