[Anticancer effect of high voltage pulses combined with concentration dependent anticancer drugs on Lewis lung carcinoma, in vivo].

Using high voltage pulse (initial electric field strength 3kV/cm, duration 4 msec, applied energy 14.9 joule) as a local load, and concentration dependent anticancer drugs such as peplomycin (PEP) 20 mg/kg, cyclophosphamide (CPA) 100 mg/kg, mitomycin C (MMC) 3 mg/kg and cisplatin (CDDP) 5 mg/kg administrated intraperitoneally, the effects on the suppression of primary lesions and on formation of pulmonary metastasis in the spontaneous pulmonary metastatic system of Lewis lung carcinoma were investigated. Though only CPA among single administrated anticancer drugs showed a suppressive effect against tumor growth, remarkable reduction in the size of primary lesions was obtained with a combination of high voltage pulse and an anticancer drug, regardless of various kinds of drug. A maximal ratio of size before and after treatment was 0.05 in PEP, 0.2 in CPA, 0.38 in MMC and 0.14 in CDDP. A combination of PEP or CPA with high voltage pulse had a particularly good effect, reducing the volume of the primary tumor after treatment less than levels before treatment throughout 2 weeks. The use of high voltage pulse alone did not affect any growth kinetics of the primary lesion. The number of pulmonary metastatic nodules was significantly reduced only by CPA among various kinds of single administrated drugs, whereas it was reduced by all treatments with a combination of high voltage pulse and each anticancer drug. The use of high voltage pulse alone did not result in any increase of the number of pulmonary metastatic nodules.(ABSTRACT TRUNCATED AT 250 WORDS)