Effect of combined epidural anaesthesia on tumor-infiltrating lymphocytes in lung adenocarcinoma: a prospective exploratory sub-analysis.

BACKGROUND: Regional anaesthesia may have advantages in preserving immune function. Tumor-infiltrating lymphocytes (TILs) are considered indicators of immune response in the tumor microenvironment and used as a prognostic marker in patients after cancer surgery. This study investigated the effects of combined epidural anaesthesia on the number of TILs in patients undergoing surgery for lung adenocarcinoma.

METHODS: Patients undergoing radical resection for primary lung cancer were randomized to receive either combined epidural-general anaesthesia (Epi-GA) or general anaesthesia (GA) in an ongoing randomized controlled trial (ChiCTR-TRC-14004136). Excised adenocarcinoma specimens from patients enrolled between 1 June 2015 and 30 November 2015 were selected for immunohistochemical staining of CD8 and FOXP3 molecules. The numbers of positive lymphocytes were counted and expressed as the number of cells per mm2 tumor area.

RESULTS: One hundred and twenty-eight patients were recruited and randomized; 64 patients were included in immunohistochemistry analysis (37 received Epi-GA vs. 27 received GA). The number of CD8+ T cells was higher in the Epi-GA group than in the GA group (median [interquartile range]: 292.8 [198.0-418.3] vs. 204.7 [131.1-305.8], P = 0.036); whereas the number of FOXP3+ T cells was less in the Epi-GA group than in the GA group (37.6 [14.7-92.3] vs. 99.8 [68.9-168.3], P < 0.001).

CONCLUSIONS: For patients undergoing surgery for lung adenocarcinoma under general anesthesia, use of epidural anaesthesia increased CD8+ T cells infiltration but decreased FOXP3+ T cells accumulation in tumor tissues. Epidural anaesthesia may affect TILs in a manner that preserves immune function.