Electrochemical modification of tumor growth in mice

We evaluated the effect of direct electrical current on large tumors in mice. Lewis lung carcinoma greater than 1 cm in the shortest dimension was treated percutaneously with 20 mA for 15 min. Separate groups were given one or more than one (two or three) percutaneous electrical treatments (PET). A third group was given sham electrical treatment, and a fourth group had surgical excision of the tumor. Animals in both PET groups survived longer and had smaller primary tumors at death compared with the sham group. PET did not alter the systemic course of the disease, judged by lung and spleen weights and by histological observation of the extent of metastatic burden in the lung. Surgery resulted in long-term survival of 17% and an increase in average survival time compared with both PET and sham treatment. PET produced rapid and polarity-dependent alterations in physiological solutions in vitro, and it is likely that similar electrochemical processes mediated the observed reduction in tumor growth. PET is potentially useful as an adjuvant modality because it reduces local tumor mass but does not alter the extent of metastasis.