POTENTIATION OF RADIOTHERAPY BY NONTOXIC PRETREATMENT WITH COMBINED VITAMIN-C AND VITAMIN-K-3 IN MICE BEARING SOLID TRANSPLANTABLE TUMOR

Background The effect of intraperitoneal and oral pretreatment with co mbined vitamins C and K-3 on the single dose radiotherapy of a transpl antable solid mouse tumor have been investigated Materials and Methods : Groups of mice bearing intramuscularly transplanted liver tumors, we re orally and parenterally pretreated with combined vitamins C and K-3 and locally irradiated with single noses of 20, 30 or 40 Gy of X-rays . After this treatment tumor dimensions were measured twice weekly and the approximate tumor Volume in groups Of pretreated with vitamins an d irradiated mice was compared to the groups of mice only irradiated a nd to the absolute control groups without any therapy Results: This no ntoxic pretreatment produced statistically significant potentiation of radiotherapy induced by 20 to 40 Gy of X-rays doses in groups of 11 t o 20 mice. Combined vitamins C with K-3 most probably constitute a red ox-cycling system producing hydrogen peroxide and other active oxygen species to which cancel cells are selectively sensitive due to their f requent deficiency in enzymatic defense system against free oxyradical s aggression. Conclusios: A possible introduction of such nontoxic and selective potentiation procedure into classical protocols of human ca ncer therapy appears to be generally accessible and without any additi onal risk for patients.