Combined treatment of murine SA-l tumors by human leukocyte interferon alpha and electrotherapy

Antitumor effectiveness of human leukocyte interferon alpha (IFN-a) was assessed in combination with electrotherapy. Subcutaneous fibrosarcoma SA-I tumors were treated with IFN-a for five consecutive days. The results indicate that IFN-a given either locally (peritumorally) or systemically (intraperitoneally) as a single treatment has moderate antitumor effect. In order to potentiate its effectiveness, IFN-a was combined with electrotherapy. Low level direct current ranging from 0.2 to 1.2 mA for 60 minutes was delivered via Platinum/Iridium electrodes placed subcutaneously, outside the tumor. Combined treatment with electrotherapy and IFN-a given intraperitoneally, proved to have more than additive antitumor effect, assessed by tumor growth delay. Interaction between the two treatment modalities increased at higher current levels used for electrotherapy. The results indicate that IFN-a and electrotherapy interact in local tumor growth control. Therefore, electrotherapy can be used to locally potentiate systemic IFN-a treatment or vice versa, the latter agent can potentiate the effect of electrotherapy.