[Experimental studies of plasma exchange therapy for malignant tumor].

We conducted the experiment to evaluate the effect of plasma exchange in treatment of cancer. Donryu rats of 8-10 week old female were used: 1 X 10(6) AH109A were inoculated subcutaneously in the back of rats. We performed comparative study on four groups: 1) untreated group; 2) plasma exchanged group; 3) MMC treated group; and 4) plasma exchange + MMC treated group. Plasma exchange was conducted from 8th day of the tumor inoculation for three consecutive days. The plasma contained in 6ml blood was taken out from the tumor-bearing rats and same volume of fresh frozen normal serum was replaced. MMC (0.5 mg/kg/day) was administered intraperitoneally from 13th day of the tumor inoculation for five consecutive days. Efficacy of plasma exchange therapy was evaluated by tumor inhibition effect as well as by 50% survival time. Plasma exchanged group showed no tumor inhibition effect, however a considerable extention of survival of 36 days was observed compared with the untreated group (29.3 days). Five out of 14 cases of MMC treated group showed tumor inhibition effect and survived for 36.5 days. Six out of 10 cases of plasma exchange + MMC treated group showed tumor inhibition effect and the survival time was 49 days. The above findings indicate: plasma exchange therapy has effects on prolongation in survival time, but has no effects on tumor inhibition and; a combination of plasma exchange and chemotherapy (MMC) produces greater tumor inhibition effect and longer survival compared to plasma exchange therapy alone and chemotherapy alone.