A simple experimental model for measuring the effectiveness of preoperative irradiation.

The use of preoperative or immediately postoperative radiotherapy and/or chemotherapy has evoked great interest. It has been shown that these modalities can reduce the tendency of neoplasms to metastasize or to implant locally at the time of surgery (1, 2, 5, 6, 8). For experimental purposes, tumor transplantability can be used as an index of this tendency. But a variety of factors may modify the ability of a tumor transplant to take. Further studies are in order on the modification of tumor transplantability (3, 7, 9, 10, 11) by (a) the age of tumor at time of transplant, (b) the size of radiation dose and (c) its fractionation, (d) the lapse of time between irradiation and transplantation, (e) the homograft reaction or immune effect, (f) preoperative vs. postoperative measures, and (g) various chemotherapeutic agents, alone or in combination. By modifying a method of tumor transplantation suggested by Haverback and Smith (4), among others, we have developed a simple experimental model which simulates co...