Intrapleural application of human leukocyte interferon (HLI) in breast cancer patients with ipsilateral pleural carcinomatosis.

Seven patients with ipsilateral pleural carcinomatosis from breast cancer were treated by intrapleural application of a crude interferon-alpha (IFN-alpha) preparation (HLI). In 4 patients, previous systemic treatment had been without effect, and 3 patients had recurrence after initial remission. Pleural carcinomatosis was confirmed by cytology in 6 patients and by histology in 1 patient. HLI was given in doses of 2.2 X 10(6) IU two to six times. The effect was evaluated by cytological examination of the pleural fluid; malignant cells disappeared in all six patients who were evaluable. Pleural fluid, while not totally resolving, did not accumulate further after HLI. Disseminated tumor was present in all at the time of eventual death. No tumor was found in the pleura at autopsy of 2 patients and the pleural fluid was free of malignant cells at the time of last follow-up examination in the 4 others. These results seem to justify further investigation on larger groups of patients with better technique of application.