Relationship between primary tumor volume and lung metastasis in Lewis lung carcinoma (II). Tumor bed effect

The incidence of lung metastases from tumors which had the tumor bed effect (TBE) was investigated in Lewis lung carcinoma in male C57BL/6 mice. Tumor cells (1-3 x 10(5] were injected into the muscle of the right hind legs which had been locally irradiated with 15 Gy of gamma rays 1 hr or 1, 4, 7, 10, or 14 days previously. The latent periods for tumor appearance were almost the same as in the controls. Compared to the controls, growth delays were observed from about 7 days after tumor cell injection. For metastasis from tumors which had the TBE, although the first development of metastasis was not different from the controls, the total number of metastases was reduced. The incidence of metastases varied according to growth of the primary tumor. The correlation between the primary tumor volume and the incidence of metastases also showed a linear relation, as in the controls. These results indicate that metastasis from tumors growing in pre-irradiated sites depended on the TBE of the primary tumors.