The clinical value of interferons as antitumor agents

Abstract

In this article the evidence pertaining to the perspectives for clinical applicability of interferons as antitumor drugs is critically reviewed. The mechanisms by which interferons can influence tumor growth and host defense against tumor proliferation are: a direct inhibitory effect on cell growth, alteration of cellular surfaces and immunomodulatory effects. In a particular situation several of these mechanisms may act syngergistically. In experiments on tumor-bearing animals the effect of interferon therapy consists of inhibition of tumor progression rather than induction of regression. Furthermore, the studies with animal models suggest that doses higher than those given in current clinical trials will be necessary to obtain clearly beneficial effects in man. Clinical trials with leukocyte interferon are well advanced, especially with regard to breast cancer, lymphoma and myeloma. They suggest that fairly small doses can cause tumor regression in some but not all cases. Regressions were also seen in all treated cases of laryngeal papilloma. Leukocyte interferon therapy might be useful to prevent metastasis after surgical removal of the primary tumor in osteosarcoma patients. Clinical trials with fibroblast interferon are less well advanced and the available evidence is rather fragmentary. No clinical trials have so far been done with immune type interferon.