The anti-metastatic effect of intravenously-inoculated BCG on prostate tumor cells.

The complication of metastasis from the primary tumor site to the distant organ is difficult to control. Tumor cells usually spread through the vascular system: lymphatics and/or blood; or by direct extension into adjacent sites. Transplantable prostate adenocarcinoma (PA-III) cells in L-W rats produces a tumor in the implant site and then spreads via the ipsilateral lymphatic route to the lungs in which new visible tumors develop. Viable bacillus Calmette-Guerin (BCG) was inoculated SC or IV into rats which were then inoculated either SC or IV with PA-III cells. They were examined thereafter for primary and for lung tumors. IV-inoculated BCG generated a strong intravascular intervention mechanism on metastatic PA-III cells in L-W rats. This immobilization mechanism was not demonstrable in rats that had been inoculated SC with BCG.