Prognostic significance of natural killer cell activity in patients with gastric carcinoma: A multivariate analysis

OBJECTIVE: Natural cytotoxicity, mediated by natural killer (NK) cells, has been believed to play an important role in inhibiting experimental tumor m etastasis, and diminished NK cell activities leads to a high incidence of t umor occurrence. Despite convincing evidence from experimental studies, the role of NK cells in the immunological surveillance against cancer in human is poorly defined. METHODS: The present study was based on a retrospective analysis of data on 156 patients with gastric cancer, who were surgically treated in the Depar tment of Surgery II, Kyushu University Hospital from 1993 to 1996. All pati ents were examined for NK cell activity based on a peripheral blood samplin g done preoperatively. RESULTS: Significant association between NK cell activity and clinicopathol ogical parameters including tumor size, lymphatic involvement, vascular inv olvement, and lymph node metastases was evident. When comparing the two gro ups according to NK cell activity, tumors with low NK cell activity tend to have lymphatic involvement. The 5-yr survival rates were 94.6% and 72.3% f or those with NK cell activity >25% lysis and less than or equal to 25% lys is, respectively, the value being statistically significant (p < 0.05). The independent risk factors for prognosis examined by logistic regression ana lysis were lymphatic involvement, NK cell activity, depth of tumor invasion , and lymph node dissection. CONCLUSIONS: These current data showed that NK cell activity may be related to tumor volume and dissemination. Measurement of preoperative NK cell act ivity may be pertinent for the prognosis of patients with gastric cancer an d for follow-up clinical management.