[Hypoxic radiotherapy. The radioprotective effect of acute hypoxia in the radiotherapy of tumors in the abdominal area].

AIM

We tested, whether inhalation a of gas mixture containing 8.0 to 8.5% O2 reduces the radiosensitivity of healthy tissue in order to deliver higher tumor doses without increasing the side effects of radiation therapy.

PATIENTS AND METHODS

In this study 165 patients were treated in the Clinic of Radiation Oncology Erlangen (Germany) and in the Institute of Oncology in Brno (Czech Republic) in the period of January 1986 to December 1993. In 108 patients external irradiation was applied using acute hypoxia (group A--hypoxyradiotherapy). This group was compared with a conventional therapy group of 57 patients (group B). The majority of the patients had advanced tumor of cervix uteri or of rectum. In 89% of patients of group A and in 61% patients of group B external irradiation was applied with portals > 20 x 15 cm2 (p < 0.01). The mean dose in the group A was increased about 30% compared to the mean dose of group B (55.2 Gy vs. 43.6 Gy; p < 0.01).

RESULTS

Despite this increase in dose and large-field irradiation in most cases in group A no differences were found between group A and B concerning acute or late effects of radiation therapy.

CONCLUSION

The aerogen acute hypoxia (hypoxyradiotherapy) is so far not only the simplest, but also one of the most effective selective radioprotective methods.