OUR EARLIER WORK documented that surgical reduction of large and well-established transplantable tumors permits noncurative courses of appropriate anticancer agents to completely eradicate the residual remnants of established tumor tissue.1,2 The probability that these findings were generally applicable was suggested by the variety of agents (6-mercaptopurine, thio-tepa, cyclophosphamide [Cytoxan], 6-aminonicotinamide and puromycin) demonstrated to produce these results, and the multiple types of tumor (RC, Sarcoma 180, Walker 256) employed in 3 strains of mice and in 1 rat tumor.
The present communication reports data demonstrating immune mechanisms as responsible for the observed inverse relationship between chemotherapeutic cure and tumor size (that is, the smaller the tumor, the greater the chemotherapeutic cure rate). In addition, chemotherapeutic cure of spontaneous tumors by means of the above experimental design is also reported.
Materials and Methods
The animals, housed in stainless steel and plastic cages, with ad libitum access to food (standard laboratory