Immunological impact of neoadjuvant chemoradiotherapy in patients with borderline resectable pancreatic ductal adenocarcinoma.

BACKGROUND

Little is known about the immunological effect of neoadjuvant chemoradiotherapy (NACRT) in the tumor microenvironment of pancreatic ductal adenocarcinoma. The objective of this study was to examine the immunological modifications induced by NACRT in patients with pancreatic cancer.

METHODS

Fifty-two patients with pancreatic cancer who underwent surgical resection were enrolled in this study. NACRT was administered to 22 patients, whereas the other 30 patients underwent surgical resection without NACRT. The resected tumor specimens were analyzed for the presence of tumor-infiltrating lymphocytes by using immunohistochemical staining for CD4, CD8, CD68, CD163, Foxp3, and major histocompatibility complex class I (MHC class I) antigen.

RESULTS

The number of CD4+ and CD8+ lymphocytes was significantly higher in patients who received NACRT than in those who did not receive NACRT. No significant difference in MHC class I expression was observed between the groups. In the NACRT group, patients with a high accumulation of CD8+ cells experienced longer overall survival than those with a low number of CD8+ cells.

CONCLUSIONS

NACRT may induce the accumulation of CD4+ and CD8+ cells in the tumor microenvironment and a high accumulation of CD8+ cells might be a good prognostic marker for pancreatic cancer treated with NACRT.