Administration of fibroblast interferon to patients with advanced breast cancer: possible effects on skin metastasis and on hormone receptors.

Eleven patients with metastasized breast cancer received 8 intramuscular injections of 6 x 10(6) units of human fibroblast interferon over a period of 40 days. The injections did not cause local irritation or inflammation. Fever occurred in only 1 of the 11 patients. Although several types of metastases were monitored, only skin nodules consistently (10 out of 11 patients) exhibited changes that were suggestive of a therapeutic effect of the treatment regimen: either a simple decrease in size of some nodules or central necrosis accompanied by an inflammatory reaction. NK-activity of peripheral blood leukocytes was significantly increased after administration of the first dose; the effect of subsequent injections was less clear. Receptors for estrogens and progestogens were increased in the tumor biopsies of 2 out of 2 and 5 out of 6 patients tested respectively.