Local regional promotion of tumor growth after abdominal surgery is dominant over immunotherapy with interleukin-2 and lymphokine activated killer cells

Various investigators have shown that tumor growth can be facilitated by surgery, that an operation can suppress immune functions, and that these phenomena may be related. With a murine intraperitoneal (i.p.) tumor model, we investigated whether an operation could promote tumor growth and, if so, whether this effect could be successfully overcome by immunotherapy with interleukin-2 (IL-2) and lympokine activated killer (LAK) cells. Treatment with IL-2 and LAK cells was highly effective in unoperated mice. When a laparotomy was done 4 days before i.p. tumor inoculation, tumor growth was enhanced in all experiments, and the effect of immunotherapy was completely abrogated. This effect was local regional; an incision on the back of the mice did not affect tumor growth or outcome of treatment. Tumor growth in the scar area was usually excessive. Furthermore, these effects were found to be temporary. Promotion of tumor growth and abrogation of IL-2 + LAK effects were seen only from 4 days to up to 2 weeks after laparotomy but were lost 5 weeks after surgery. These results suggest that growth factors present in healing wounds may cause promotion of tumor growth and are dominant over the effects of IL-2 and LAK cell therapy.