Antitumor effect of electrochemical therapy on transplantable mouse cancers

The aim of our study was to assess the antitumor effect of electrochemical therapy (ECT) in the mice bearing advanced transplantable tumours. Mouse mammary cancer 16/C (group 1) and fibrosarcoma F69-3 (group 2) were transplanted subcutaneously (s.c.) into the C3H or BALB/c mice, respectively. Twenty animals in each group bearing measurable s.c. tumours were randomly divided into two subgroups (experimental and control). Two electrodes were inserted into tumours and low level direct current (6-7 V, 5-21 mA) was passed. The animals were observed and tumors were measured twice a week. The animals were sacrificed and autopsied when the tumor diameter reached 2.0 cm. Two animals of each group (experimental and control) were sacrificed for histopathological tumor examination on the 1st and 6th day after ECT. A significant inhibition of tumor growth in mice subjected to ECT was observed, both in those with s.c. growing mammary cancer and with fibrosarcoma. This inhibition was associated with marked prolongation of survival time of ECT-treated mice. It appeared that the mice with mammary cancers were more susceptible to ECT therapy than those with growing s.c. fibrosarcoma. The histopathological studies of tumor specimens from ECT-treated mice showed extensive foci of necrosis with shrinkage of cell nuclei deprived of chromatin. In conclusion, the treatment which inhibits the growth of experimental mammary and fibrosarcoma tumors was demonstrated. However, in no mice complete regression of tumours was observed.