Klin Onkol 1998; 11(4): 123-126.
Summary: Tolerance of normal tissues to an accelerated pre-operative hypoxiradiotherapy for rectal carcinoma was evaluated in 50 patients. Irradiation was performed with a linear accelerator, acute hypoxia was achieved by inhalation of a gas mixture containing only 7.8-8.0% of oxygen, and the dose of radiation was administered in fractions of up to 4 Gy/day. The patients were subdivided according to the applied dose into three subgroups treated with 24 Gy in 8 days (5 patients), 28 Gy in 9 days (20 patients), and 32 Gy in 10 days (25 patients). Tumors were resected by low anterior resection or abdominoperineal excision of the rectum the following day after completion of hypoxiradiotherapy. As a result, the early post-irradiation reaction is negligible despite the applied dose and no hypoxiradioiherapy-related intra-operative or post-operative complications were observed. There were no late problems after treatment of rectal cancer which could be related to this type of pre-operative irradiation. Due to the radioprotective effect of hypoxia, the overall duration of pre-operative radiotherapy could be reduced by 70% and patients were radiation side effects - free during this shortened treatment. This modification of pre-operative radiotherapy of rectal carcinomas might be more biologically effective and could improve the clinical results on final evaluation.
