Minimally invasive colorectal surgery may have a less pronounced inflammatory response

Minimally invasive colorectal surgery may have a less pronounced inflammatory response and less of a suppressing effect on the immune system than conventional surgery, resulting in a possible reduction in post-operative complications, according to a study in the July issue of Archives of Surgery.

Minimally invasive (laparoscopic) techniques have become more common for colorectal surgery and may be associated with reduced rates of post-operative bowel obstruction, wound infection and cardio-respiratory complications, according to background information in the article. There have been reports of reduced inflammation and other indications of suppression of the immune system following laparoscopic surgery, which may have implications for the long-term prognosis of patients with cancer, the authors suggest.

Matthias W. Wichmann, M.D., of Ludwig-Maximilians University, Munich, Germany, and colleagues took blood samples from 70 patients with colorectal disease undergoing laparoscopic (35) or conventional (35) surgery, before surgery and on one, three and five days following surgery. The blood was examined to determine the levels of white blood cells involved in the immune response, including B-cells, T-cells and natural killer cells, white blood cells that attack foreign bodies or abnormal cells, as well as levels of two molecules involved in the inflammatory response, interleukin 6 (IL-6) and C-reactive protein (CRP).

The researchers found that although the levels of the inflammatory markers CRP and IL-6 increased after both types of surgery, the levels were significantly higher in patients who had undergone conventional surgery. The levels of natural killer cells were significantly higher in patients undergoing laparoscopic surgery. The levels of other white blood cells, including the B-cells and different types of T-cells were depressed in all patients, with no significant differences.

"The long-term effects of immunosuppression in response to treatment and development of metastases [the spread of cancer beyond the original tumor] still remain obscure," the authors conclude. "However we can assume that our observation of better preserved nonspecific immunity [natural killer cells] in patients after laparoscopic colorectal surgery has beneficial effects on perioperative infectious complication rates--which is true for patients with benign as well as malignant colorectal disease."