Chemotherapy-induced pulmonary toxicity in mice bearing L1210 leukemia

Fatal pulmonary toxicity can be consistently produced in L1210 leukemia-bearing mice by single therapeutic doses of cyclophosphamide, BCNU, and mitomycin C but not by adriamycin. Lung toxicity is principally determined by an existing tumor burden at the time of drug administration. Thus when any of the four chemotherapeutic agents was given 5 days after L1210 transplantation there was no mortality. Pulmonary pathology in these mice was equivalent to that noted in normal mice receiving identical drug treatment or to that noted in untreated L1210-bearing mice sacrificed 7, 8, or 10 days after tumor transplantation. When chemotherapy was delayed to day 7 after L1210 transplantation for mitomycin C or to day 8 after transplantation for BCNU and cyclophosphamide, more severe pulmonary toxicity was found. Mortality within the first 5 days of treatment was 38, 50, and 80%, respectively. Pulmonary pathology included moderate to severe vascular congestion and interstitial pneumonitis, diffuse pulmonary hemorrhage often involving the entire pulmonary parenchyma, pulmonary edema, and alveolar cell metaplasia. A unique finding, associated with cyclophosphamide treatment, was the occurrence of perivascular-intramural edema of the walls of medium-size pulmonary vessels. It is hypothesized that stasis within the pulmonary capillary circulation, resulting from advanced tumor growth and from drug treatment, may contribute to the development of chemotherapy-related toxicity.