Combined treatment of autochthonous 3-methylcholanthrene-induced murine tumors by immunotherapy and radiotherapy.

C57BL/6J mice with autochthonous 3-methylcholanthrene-induced tumors were given combined therapy with 2,000 rad of local irradiation and regional injections of cell-wall skeleton of Nocardia rubra (N-CWS). The greatest suppression of the tumor growth and the highest survival rate were observed in the combined treatment group as compared to the non-treated control, regional injections of N-CWS alone and irradiation alone groups. In addition, pulmonary metastasis was significantly suppressed by the combined therapy.