Pilot study of interaction of radiation therapy with doxorubicin by continuous infusion.

Doxorubicin was initially administered alone by continuous infusion for 5 days every 3 weeks in escalating doses to 13 patients with advanced metastatic and/or recurrent malignancies. The maximum tolerable dosage was 13 mg/m2 per day for 5 days. Kinetic data showed a steady level of 60 ng/ml for 4 days and a biphasic disappearance curve. Radiation therapy (150-200 cGy per session) was then administered in 5-day cycles, every 3 weeks, concomitantly with continuous infusion of doxorubicin (12 mg/m2 per day) to 21 patients with various advanced unresectable recurrent or metastatic malignancies. Four of 9 patients with soft tissue sarcomas achieved complete response after a radiation dose of 2,206 +/- 590 (SD) cGy and 3 had partial response; the median durations of the response were 142 +/- 65 (SD) weeks for complete response and 28 +/- 10 weeks for partial response. Of 4 patients with primary hepatoma, 2 achieved partial response after 1,290 +/- 210 cGy. No response was seen in any of the 7 patients with adenocarcinoma of the gastrointestinal tract or breast. Complications of this regimen included moderate leukopenia and thrombocytopenia, mucositis, skin erythema, and decrease of the ventricular ejection fraction at a cumulative doxorubicin dose of 840 mg/m2. We conclude that doxorubicin given by protracted infusion can be safely administered with concomitant radiation and appears to enhance the effects of radiation on most soft tissue sarcomas and on some hepatocellular carcinomas.