Lymphogenous and hematogenous metastasis of Lewis lung carcinoma in the mouse.

Quantitative and temporal comparisons were made between lymphogenous and hematogenous metastasis in the non-immunogenic model system of mice bearing transplanted 3LL tumors in their hind feet. The experimental evidence indicates that cancer cells disseminate from clinically detectable primary cancers by non-exclusive routes in the blood-stream and in the lymphatics. Following a delay of approximately 2 weeks after injection of 3LL cancer cells into the foot, local lymph-node micrometastases occur, together with the first appearance of overt hematogenous metastases in the lungs. The anatomic extent of lymph-node involvement, determined by bioassays of orthotopic grafts, of ipsilateral popliteal, inguinal and lumbar nodes, provides an accurate indicator of hematogenous metastasis, even though lymphogenous and hematogenous metastasis are operationally independent in this tumor/host system.