Effects of varying potential and electrolytic dosage in direct current treatment of tumors

The effects of different voltages and dosages during direct current treatment were studied to determine the most effective tumor treatment. Groups of nude mice with subcutaneous human colon cancer nodules were treated with a single electrolytic dose (charge) of direct current using two percutaneously placed needle electrodes. All the treated groups responded and the residual tumor volumes were significantly lower (p less than 0.001) than the control group. 7.5 V gave the greatest tumor reduction, significantly more than for 12.5, 10.0, and 2.5 V. 35 C/ml of tumor was more effective than 30 C/ml (p less than 0.05) and no difference in response was obtained between 35 and 50 C/ml. Hyperthermia did not appear to play a significant part in direct current treatment in the examined voltage range as no intra-tumoral temperature elevation was observed. Direct current may allow effective percutaneous treatment of metastases which are unresponsive or unsuitable for conventional treatment.