In a collective of 200 Wistar rats, the influence of
anticoagulants upon the rat tail
tumor (Walker 256
carcinosarcoma) was checked with and without irradiation. After implantation of the
tumor and development of a certain definite
tumor volume, the animals were divided into four different groups of 50 rats each. The first one was the control group without any manipulation, the second received an one-stage X-irradiation with 2500 R SD directed to the tail
tumor, the third was treated with an oral dose of
Phenprocoumon which was added to the daily drinking quantity (0.1 mg/kg
body weight), and the fourth group was given an one-stage X-irradiation together with the oral
Phenprocoumon treatment. The influence of these different treatments on the growth of the primary
tumor, on the incidence of
metastases and on the death rate was checked up. The best therapeutical effect was observed with combined radiation and
Phenprocoumon treatment. The
therapy resulted in an almost complete growth rate depression of the primary
tumor, in an early tendency of remission of the primary
tumor, a 42 per cent decrease of the incidence of
metastases to the lung, and a 42 per cent increase of the survival rate. With regard to the frequency of
metastases and to the survival rate, treatment with
Phenprocoumon alone showed significantly better results as sole
radiation treatment.