Laparoscopic surgery preserves monocyte-mediated tumor cell killing in contrast to the conventional approach

Background: Experimental animal research shows that immunologic defenses ag ainst tumor cells are disturbed by surgical trauma, resulting in an increas ed rate of tumor implantation and the growth of subsequent metastases. Mini mally invasive surgery is associated with a preservation of postoperative i mmunologic functions and, in animal models, with decreased tumor growth. Th e objective was to study the influence of several surgical procedures, appr oached conventionally and laparoscopically, on interleukin-6 (IL-6) and mon ocyte-mediated cytotoxicity (MMC). Methods: Five groups of five patients each were included in this prospectiv e study: laparoscopic cholecystectomy (minor trauma) group, Nissen fundopli cation (laparoscopic and conventional as moderate trauma) groups, and sigmo id colectomy (laparoscopic and conventional as major trauma) groups. Preope ratively, 1 and 4 days after surgery, IL-6 and MMC against SW948 colon canc er cell line were determined. Results: The IL-6 levels differed significantly between the three laparosco pic procedures (p = 0.004) and increased according to the degree of trauma. There was no significant difference in MMC between the three laparoscopic procedures. However, MMC was suppressed after conventional procedures and p reserved after laparoscopic procedures (p = 0.001). There was no correlatio n between IL-6 levels and changes in MMC. Conclusions: More extensive laparoscopic procedures induce increased levels of IL-6, reflecting higher levels of trauma. Conventional surgical procedu res result in depressed MMC in the postoperative period. After laparoscopic procedures, MMC is preserved. These findings may be of importance in preve nting implantation and growth of cancer cells spread by surgical manipulati on.