Multi-modality treatment of primary nonresectable intrahepatic cholangiocarcinoma with 131I anti-CEA--a Radiation Therapy Oncology Group Study.

Thirty-seven patients with primary nonresectable intrahepatic cholangiocarcinoma (57% with prior treatment and/or metastasis) were prospectively treated with external radiation, chemotherapy, and 131I labelled anti-CEA. Therapy began in all trials with whole liver irradiation (21.0 Gy, 3.0 Gy/Fx, 4 days/week, 10 MV photons) with alternate treatment day chemotherapy (Adriamycin, 15 mg + 5-FU, 500 mg). One month after external beam therapy, chemotherapy was given (Adriamycin, 15 mg + 5-FU, 500 mg) followed the next day by the first administration of 131I anti-CEA. The treatment schedule used was 20 mCi day 0; 10 mCi day 5 as an outpatient. This schedule was derived from tumor dose estimates which indicated that 20 mCi (8-10 mCi/mg IgG) was sufficient to achieve tumor saturation with a tumor effective half-life of 3 to 5 days, depending upon the species of animal from which the antibody was obtained. The median tumor dose for the 20 mCi + 10 mCi regimen was 6.2 Gy. Antibody therapy was delivered in 2-month cycles using antibody generated in different species of animals; rabbit, pig, monkey, and bovine. Toxicity was limited to hematologic toxicity and was manifested as thrombocytopenia and leukocytopenia (3.2% Grade IV for each according to RTOG toxicity criteria). Tumor remission evaluated by CT scan digitized tumor volume analysis indicated a 26.6% partial response (PR). Tumor remission by physical examination indicated a 33.3% remission rate (25.9% PR and 7.4% complete remission (CR]. The median survival for patients who responded was 15.2 months. The actuarial median survival for the entire group of patients (metastases and previous treatment) was 6.5 months. The longest partial remission is presently more than 4 years.