Although successful treatment of patients with primary
tumor by conventional surgery and
radiotherapy is often possible, death frequently results from
tumor metastases. Since
metastasis has already occurred in many
cancer patients at the time of diagnosis, a major emphasis of
cancer treatment is and will continue to be the prevention or successful management of
tumor metastases. Systemic
chemotherapy has been widely used in the past in the hope of preventing or controlling
micrometastases. The results of this treatment have been disappointing with little impact on survival in the vast majority of solid
tumors. Bio-
immunotherapy has emerged as another modality and is finding acceptance and use in treating patients with
cancer. The role of bio-
immunotherapy in traditional surgery,
radiotherapy,
chemotherapy and
hyperthermia will be discussed. In order to evaluate new and innovative treatments, we and others have used murine models of
erythroleukemia and solid
tumors with metastatic potential to assess the effects in vivo of bio-
immunotherapy.
Tumor metastases can be dampened and immunosuppression restored by bio-
immunotherapy, especially when used in combination with other forms of treatment. Most of the combination treatments used in animal models are encouraging but are by no means totally adequate or curative yet. The molecular basis of
cancer is now understood to involve activation of dominant oncogenes and inactivation of tumor suppressor genes. These genetic events may represent novel targets for
cancer treatment. The potential use and ethical implications of gene transfer to alter the behavior of somatic cells in patients with
cancer has been noted. Also reported is genetic
immunomodulation by introducting genes for
cytokines into
tumor cells or lymphocytes to stimulate a cytotoxic immune response against the
tumor. As with bone marrow, human cord blood can be used for
transplantation in the autologous, related allogeneic and unrelated allogeneic settings, and as a target cell for gene treatment. It is believed that the greatest therapeutic results of bio-
immunotherapy, including
biological response modifiers,
cytokines, gene treatment and
bone marrow transplantation, will come in combination with other established effective modalities including surgery,
radiation treatment,
chemotherapy and
hyperthermia in the treatment of patients with
cancer.