DC TREATMENT OF CHEMICALLY-INDUCED MAMMARY CARCINOMAS IN AN ANIMAL-MODEL - MR VOLUMETRIC ASSESSMENT OF THE INFLUENCE OF THERAPY

Purpose: To investigate the effect of direct current treatment (DCT) o n the growth of mammary carcinomas in rats by MR-volumetry. Methods: C hemically induced mammary adenocarcinomas in a control group (n=17) we re compared with treated rumours (18 C/cm(3) in group A: n = 7 or 36 C /cm(3) in group B: n = 12). 31 untreated rumours were situated near a treated tumour (group C). Experiments were carried out using one posit ive electrode in the tumour centre and three negative electrodes in th e periphery. The tumour volume was measured by MRI before, and 1, 3, 6 , 9 and 12 weeks after treatment. Results: 12 weeks after DCT, the mea n tumour volume in group A (164% +/- 158%, p<0.05) and group B (13% +/ - 24%, p<0.001) was significantly reduced compared to the control grou p (434% +/- 230, Mann-Whitney U-Test). Complete tumour regression occu rred in 42% of rumours in group B and was not achieved in group A, C a nd control group. Tumour growth in group C was decreased compared to t he control group. Conclusions: The effectiveness of DCT was found to d epend on the applied dosage - 36 C/cm(3) was more effective than 18 C/ cm(3). The effect of DCT is not limited to the area between the electr odes.