There is no doubt that cancer cells do enter the circulating blood of persons with malignant lesions. Differentiation of them from other atypical cells found normally in the bloodstream is at present being studied. Investigators have expressed belief that most of the circulating malignant cells in the early stages of the disease are destroyed by host resistance. Surviving cells, however, develop into occult metastatic emboli which may remain quiescent until host defenses collapse. Clinical measures for the active control of these dormant implants have not been evolved as yet. Inasmuch as the mechanism of host resistance is still beyond clinical comprehension, the only known way to improve survival rates is the universal application of practical clinical methods for preventing iatrogenic disseminations, for devitalizing malignant cells and for apprehending emboli that may have left the main lesion just before surgical operation. Since it adequately eradicates primary sources of cell dissemination, conventional radical resection is still the treatment of choice for dealing with early solid neoplasms.