The current management of a cancer patient may or may not be curative: this depends on the presence and extent of metastases from the primary malignancy at the time of its surgical removal. Many localized malignancies can be managed satisfactorily by well-standardized methods of treatment. However, following resection of malignant lesions which appear to be localized and completely resectable at surgery, nondetectable metastases often become apparent at a later date. Tumor metastasis results from cancer cells leaving the primary tumor and migrating via either blood vessels, lymphatic channels, or intracellular spaces into adjacent tissues. To become a metastatic tumor implant, the cells must locate in another tissue and grow. Current indications are that this process occurs similarily in man and in animals used in experimental study.
The detection of distant metastatic tumors usually precludes any attempt to surgically cure the patient of his disease. Under these circumstances, a patient's therapy