Long-term adjuvant interferon treatment of human osteosarcoma. A pilot study.

During the period from 1971 to 1990 all osteosarcoma patients referred to the Karolinska Hospital without signs of metastases received human leukocyte interferon (IFN) as adjuvant treatment. Patients referred between 1985 and 1990 were given more intensive human leukocyte IFN treatment, i.e. a standard dose of 3 MU s.c. daily for 3-5 years. These 19 patients, all followed for 5 years, were included in a pilot study which entailed patients with central localization where radical surgery was not feasible. Metastases developed in 9 patients, of whom 3 had local recurrences. Sixty-three percent are free of disease at 5 years. Side-effects were negligible and long-term toxicity practically non-existent. It is suggested that a randomized multicenter IFN trial should be instituted on patients with poor prognosis receiving chemotherapy and/or that IFN treatment should be combined with other therapeutic modalities--irradiation, chemotherapy or anti-angiogenic substances--in osteosarcoma.