| Abstract: | Combined radiotherapy and nonspecific adjuvant C. parvum or Piromen treatment of rat tumors show improvement over radiotherapy alone. The most effective protocol, resulting in complete remission in 6 of 6 rats was obtained with C. parvum given i.p. in three doses 1 day prior to tumor X-irradiation of three doses of 1500 R each given on days 1, 4, and 8. Animals receiving the same dose schedule without adjuvant had only partial regression of their tumor. Without adjuvant, increasing the dose to 6000 R also resulted in tumor regression, but at the expense of marked necrosis to the leg. One mechanism for the observed results may be stimulation of the reticulo-endothelial system to produce macrophages activated against the tumor. It is also possible that C. parvum causes increased rate of clearance of soluble antigens released as a result of radiation destruction of the tumor, as suggested by Proctor et al (3). |
