Preoperative natural killer cell activity: correlation with distant metastases in curatively research colorectal carcinomas.

The authors investigated whether host immunity contributes to the development of asynchronous distant metastases in colorectal carcinomas. The host immunity was examined 8 times, pre- and postoperatively during a one year period in 77 curatively operated cases. A prospective study was performed using obtained personal data. During the mean follow-up period of 920 days, 13 patients developed distant metastases. Among the immunological parameters, the preoperative natural killer (NK) cell activity differed significantly between the metastases positive and negative groups. On univariate analysis, dichotomous NK activity, presence of nodal metastases, and venous invasion correlated with metastases. The hazard ratios on multivariate analysis were 4.53, 3.82, and 4.81, respectively. No correlation was noted between NK activity and the progression stages of colorectal carcinomas. These data suggested that attenuated preoperative NK activity is an important background factor for the development of asynchronous distant metastases following curative resection of colorectal carcinomas.