Inhibitory effect of Cystenosine on leukopenia by radiation

Cystenosine, composed of Cysteine and Inosine, was given to the patients with malignant tumors during radiotherapy. As radiotherapy, lineac x-ray 60Co-γ ray, and 4 MV-betatron were used. Except betatron, a daily dose of 200 to 250 rads was given four times a week, and a total dose reached 5000 to 6000 rads. Administration of Cystenosine was started simultaneously with the onset of the radiotherapy, and 6 tablets a day were given. Of 40 subjects, the drug was very effective in 45 per cents, effective in 37.5 per cents, and ineffective in 17.5 per cents. The effective rate was 82.5 per cents, if the cases with effective and very effective were considered as effective. Of the patients, in whom irradiation field was larger than 15 x 15 cm, the drug was effective in 67 per cents and ineffective in 33 per cents. On the other hand, it was effective in 95 per cents of the patients, in whom irradiation field was middle or small and the size was under above size. Carcinostatic substances were concomitantly given to many of the patients, in whom malignant lymphoma and breast cancer were metastasized in a large extent. In 7 of 9 patients (77.8 per cents), hematopoietic disturbances were inhibited, and prearranged courses of therapy were effectively completed. Although the variation of the number of the blood platelets was not always parallel to that of leukocytes, interruption of the treatment because of the decrease of the blood platelets was found in none of the patients. Neither subjective not objective side effects were seen after the administration of Cystenosine. (Kumagai, S.)