Studies on the Effects of Surgery on Transplanted Animal Tumors and Their Metastases

Abstract

The effects of amputation of the primary tumor on the development of metastatic lung tumors were studied in 3 transplanted mouse tumor systems. Complete amputation of the primary tumor sharply reduced the number of metastatic foci. Controls had numerous small foci, but amputees had fewer but larger foci. Since amputees live longer, their lung tumors eventually became extremely large and sometimes completely covered the surface of the lungs. Incomplete removal of the primary tumor did not significantly alter the number of metastatic foci. Instead, it yielded results similar to those for unamputated controls, which suggested that surgical trauma per se does not result in enhanced formation of metastases. Amputation of the primary tumor also reduced the number of lung metastases in both aged mice (1 year) and relatively young mice (6 and 12 weeks). A lesser rate of primary tumor growth was noted for the aged host.