Chemotherapy studies in autochthonous rat tumors: hepatomas.

Diethylnitrosamine (DEN) was applied orally to a total of 250 female Wistar rats in a single dose (d) of 3 mg/kg body weight 5 times a week for a duration of 20 weeks. After approximately 150 days exploratory laparotomy was performed to all animals. By inspection of the liver they were divided into 4 stages of disease according to the extent of cancer formation. The reaction of rats with DEN induced liver tumors was tested using a 4-drug combination chemotherapy with different equitoxic doses of Adriamycin (Adm), Methotrexate (Mtx), 5-Fluorouracil (5-FU) and Cyclophosphamide (CP). No benefit of drug treatment could be noted. In drug treated animals no decrease in the development of the liver tumors, in the frequency of metastases nor in the frequency of tumors of other origin could be demonstrated. The parallels of chemotherapy in chemically induced liver cancer to clinical experience are discussed.