Results of electrochemical therapy of colorectal liver metastases in rats followed up by MRI.
OBJECTIVE
Direct-current or electrochemical therapy is an alternative method for local tumor therapy. Until recently, it was mainly applied in China and was relatively unknown in the Western world. This study examines the feasibility and effectiveness of applying direct-current therapy in liver metastases of colorectal carcinomas in an animal model.


METHODS
Liver metastases were implanted in 47 BDIX rats by subcapsular injection of cells from a colorectal strain (DHD/K12). The success rate of implantation and the size of the tumors were determined after 3 weeks by MR imaging (T2-weighted turbo spin-echo images; relaxation time 1,800 ms, echo time 80 ms). The direct-current therapy was applied by one platinum electrode placed in the center of the tumor and four at the periphery of the tumor. Suitable therapy parameters were established in a pilot study by comparing four different methods of direct-current therapy with a control group. The methods varied with respect to the electrode polarity and the applied voltage. In a second series of investigations, tumor growth was monitored by MR imaging 3 and 5 weeks after therapy.


RESULTS
The tumor implantation rate was 92.6% at a tumor cell concentration of 8 x 10(5)/mL. The most effective therapy method was achieved by placing an anode at the center of the tumor and four cathodes at the periphery, with an applied charge of 80 C/cm3. Complete tumor necrosis was observed in 54% of cases. In the follow-up measurements, the mean tumor diameter was 0.65 cm at 3 weeks after therapy and 0.76 cm at 5 weeks after therapy. In comparison with the control group (1.08 and 1.53 cm, respectively), this represented a significant reduction in tumor growth rate.


CONCLUSIONS
This study is the first to demonstrate an antitumoral effect of direct-current therapy on liver metastases of colorectal cancer in rats.
Maintz
D
D
Department of Diagnostic Radiology, University of Cologne Medical School, Germany.
Fischbach
R
R
Schäfer
N
N
Schäfer
H
H
Gossmann
A
A
Kugel
H
H
D000818:Animals; D016009:Chi-Square Distribution; D015179:Colorectal Neoplasms / Q000473:pathology*; D004195:Disease Models, Animal; D004599:Electric Stimulation Therapy; D004567:Electrodes, Implanted; D005240:Feasibility Studies; D008113:Liver Neoplasms / Q000473:pathology / Q000556:secondary* / Q000628:therapy*; D008279:Magnetic Resonance Imaging; D051381:Rats; D014407:Tumor Cells, Cultured