In vivo antitumor effects of electrochemotherapy in a tongue cancer model

Purpose: this study investigated the in vivo antitumor effects of electroch emotherapy (ECT) using electroporation and bleomycin in a hamster tongue ca ncer model to assess its clinical applicability. Materials and Methods: Twenty animals with chemically induced tongue cancer were divided into four experimental groups designated B-E-, B-E+, B+E-, an d B+E+. The B+E+ and B+E- groups received an intraperitoneal injection of 1 00 mu g bleomycin. Fifteen minutes after the injection, the B+E+ animals re ceived electric pulses. The B-Ef group received only electric pulses. The B -E- group received neither bleomycin nor electric pulses. Each group receiv ed the same treatment twice. The antitumor effects were assessed based on t umor volume reduction and histologic findings. Results: The B+E+ group showed remarkable tumor volume reduction, decreasin g an average to 8.8% of its original volume 14 days after the treatment. Co mplete loss of the protruding tumor was observed in two of the five animals . Histologically, the tumors of the B+E+ group consisted of severely degene rated tumor cells and desquamative keratinizing cells. No living cancer cel ls were detected in three animals. The B+E-, B-E+, and B-E- groups showed p rogressive tumor growth, exceeding 200% of initial tumor volume during the experimental period. Conclusion: The current study showed remarkable antitumor effects of ECT wi th bleomycin in the hamster tongue cancer model. ECT with bleomycin may be clinically applicable to the treatment of oral cancer.