One reason for failure to cure solid tumors by surgery appears to be the impossibility of controlling metastases that are present but latent at the time of operation. This failure is a common clinical experience with aggressive neoplasms. but it is not always appreciated in tumors with longer survival times. e. g .- breast and colon cancer. In addition. recent evidence indicates that after resection of a primary tumor micrometas- tases from it might be enhanced by suppression of immune and reticu- loendothelial functions of the host. Other factors, such as increase of coagulability and stress...