Background: Cytotoxic activity of peripheral blood lymphocytes obtained during surgery against autologous fresh tumor cells has been reported. However, the role of lymphocyte autologous tumor killing or natural killer activity during the postoperative period remains obscure. In this article, the authors describe the importance of postoperative autologous tumor killing activity as a prognostic factor in patients with primary resected nonsmall cell lung carcinoma (NSCLC) after long term follow-up.
Methods: Forty-two patients who had resection of NSCLC, with primary culture of autologous tumor cells taken successfully, were studied. Cytotoxic activity against autologous, allogenic NSCLC and K562 leukemia cells was examined using peripheral blood lymphocytes obtained during the 2 weeks immediately following surgery. Factors related to prognosis were analyzed by univariate and multivariate analyses.
Results: The overall 5- and 10-year survival rates for the NSCLC patients were 40.5% and 27.5%, respectively. Statistical analysis of survival curves revealed a significant difference with regard to T classification (P = 0.025), N classification (P = 0.0015), stage (P = 0.028), and postoperative autologous tumor killing activity (P = 0.0008); there were no significant differences in relation to age, gender, histology, differentiation, visceral pleural invasion, resectability, surgical method, allogeneic tumor killing activity, or natural killer activity. Multivariate analysis demonstrated a significant correlation between disease recurrence and N classification (P = 0.0003), T classification (P = 0.023), stage (P = 0.001), and autologous tumor killing activity (P = 0.007), indicating independent prognostic significance. The phenotypes of the effector cells involved in autologous tumor killing activity were CD3(+), CD4(-), CD8(+), and CD11b(-). Autologous tumor killing activity was inhibited by competing unlabeled autologous tumor cells.
Conclusions: Autologous tumor killing activity during the 2 weeks immediately following surgery is an important prognostic factor in resected NSCLC.