Phenotype of peripheral blood leukocytes and survival of patients with metastatic colorectal cancer.

Immune dysfunction is prevalent in metastatic cancer. Few patients with colorectal cancer metastases are cured, and among the strategies aimed at improving the therapeutic results in patients with metastatic colorectal cancer, immunotherapy is being increasingly investigated. We evaluated retrospectively the prognostic significance of peripheral blood leukocytes in 59 patients with metastatic colorectal cancer. The relative numbers of CD3+, CD3+CD4+, CD3+CD8+, NK (CD3-CD16+CD56+), CD3+DR+, CD3+CD25+, CD3+CD69+, CD19+, CD19+CD23+, CD8+CD28+, CD8-CD28+, CD8+CD57+, CD14+DR+ and CD14+CD16+ leukocytes were analyzed by two-color flow cytometry. A three-step approach was adopted to identify predictors of prognosis using regression analysis. Based on the results of univariate survival analysis, the absolute number of white blood cells, NK/CD3+CD69+ and NK/white cell count ratios were significant indicators of prognosis. In the multivariate regression analysis a model was obtained using a single parameter, the NK/CD3+CD69+ ratio, predicting the survival with 10-15% power of regression. The present results indicate that the NK/CD3+CD69+ ratio in peripheral blood may be an independent variable in a regression model predicting the overall survival of patients with colorectal cancer metastases to be tested in prospective studies.