Randomized clinical trial of the effect of open versus laparoscopically assisted colectomy on systemic immunity in patients with colorectal cancer

Laparoscopic surgery is believed to produce an attenuated metabolic stress response and to have a less dampening effect on the immune response than op en surgery. To date, the effect has not been studied in a randomized clinic al trial of colorectal cancer. The study was a two-armed randomized prospective trial conducted in paralle l with the UK Medical Research Council's Conventional versus Laparoscopic-A ssisted Surgery in Colorectal Cancer (CLASICC) trial comparing laparoscopic ally assisted colorectal surgery for left-sided tumours with conventional o pen surgery. Systemic immunity was assessed by determining the T- and B-cel l counts, the CD4 : CD8 ratio, the natural killer cell counts, the immunogl obulin (Ig) G, IgM and IgA levels, and C3 and C4 levels. The white cell pha gocytic activity (nitroblue tetrazolium test) was studied before operation and on the third postoperative day. A total of 236 patients were randomized in the immune study between 11 Marc h 1997 and 14 August 1999; 161 had complete preoperative and postoperative assays for the analysis of results. There was no difference in mean respons e between the two surgical groups for each of the immune parameters studied . The unadjusted difference for the primary endpoint, T-cell count, 3 days after operation was - 1.6 per cent (95 per cent confidence interval - 5.0 t o 1.8 per cent). There is no difference in the systemic immune response in patients having l aparoscopically assisted colectomy compared with those undergoing conventio nal open surgery for colorectal cancer.