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 ( TIL s) 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 TIL s 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 (Chi CTR ‐ TRC ‐14004136). Excised adenocarcinoma specimens from patients enrolled between 1 June 2015 and 30 November 2015 were selected for immunohistochemical staining of CD 8 and FOXP 3 molecules. The numbers of positive lymphocytes were counted and expressed as the number of cells per mm 2 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 CD 8 + 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 FOXP 3 + 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 CD 8 + T cells infiltration but decreased FOXP 3 + T cells accumulation in tumor tissues. Epidural anaesthesia may affect TIL s in a manner that preserves immune function.