Lymphocyte subsets and natural killer cell cytotoxicity after laparoscopically assisted resection of rectosigmoid carcinoma

Background: Laparoscopically assisted resection of colorectal carcinoma is technically feasible and minimally invasive. Postoperative immunosuppression also may be reduced. This study compared the lymphocyte subsets and natural killer (NK) cell cytotoxicity in patients after laparoscopically assisted resection with those after open resection of rectosigmoid carcinoma. Methods: In this study, 40 patients with rectosigmoid carcinoma, but no evidence of metastasis, were randomized to receive either laparoscopically assisted or conventional open resection of the tumor. Blood was collected before the operation, then 24 h, 72 h, and 8 days after the operation for studies of lymphocyte subsets and NK cell cytotoxicity. Results: The lymphocyte subsets and NK cell cytotoxicity of both groups showed typical suppression after surgery. The suppression of T cell activation and NK-like T cells was significantly less after laparoscopically assisted resection than in after open resection, whereas the difference in other lymphocyte subsets and NK cell cytotoxicity was not significant. Conclusion: This study showed that some cellular components of the immune system are less suppressed after laparoscopically assisted than after conventional open resection of rectosigmoid carcinoma. This may have implications for tumor recurrence and long-term patient survival.