The effect of surgery and pretreatment or posttreatment adjuvant chemotherapy on primary tumor growth in an animal model.
The Ca755 solid tumor in the C57B1 mouse has been used as a model to study the interrelationship of surgery and adjuvant chemotherapy on primary tumor growth. Surgery was performed on various days after tumor implantation. Surgical mortality increased with delay in surgery. The mean survival time (MST) was significantly increased by surgery. An increased cure rate in mice with late surgery may be due to immunological factors. Pretreatment cytoxan chemotherapy prior to a number of surgical days on the most effect schedule increased MST in the later surgical days primarily due to shrinkage of tumor and a diminished surgical mortality. Posttreatment chemotherapy significantly increased MST primarily on the basis of reducing tumor cell population after surgery and increasing both the cure rate and the time until death of those mice dying of regrowth of tumor. Optimal chemotherapy alone significantly increased MST compared to untreated controls. Optimal postsurgery chemotherapy increased survival longer than the additive increase of chemotherapy alone and surgery alone. This paper illustrates relationships between day of surgery dose and schedule of chemotherapy and effect on various measurable parameters. The results can best be understood in relationship to each other. It is suggested that adjuvant chemotherapy has specific definable benefits. It is apparent from human studies that carefully devised designs which consider these interrelationships are necessary if optimal therapeutic results are to be achieved.
D000230:Adenocarcinoma / Q000473:pathology; D000818:Animals; D003520:Cyclophosphamide / Q000627:therapeutic use; D004195:Disease Models, Animal; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009374:Neoplasms, Experimental / Q000188:drug therapy / Q000401:mortality / Q000473:pathology / Q000601:surgery / Q000628:therapy*; D013997:Time Factors
D003520:Cyclophosphamide