Prognostic Significance of Tumor-Infiltrating Lymphocytes in Patients With Pancreatic Ductal Adenocarcinoma Treated With Neoadjuvant Chemotherapy.

OBJECTIVES

The aim of this study was to examine tumor-infiltrating lymphocytes (TILs) and their prognostic value in patients with pancreatic ductal adenocarcinoma (PDAC) after neoadjuvant therapy.

METHODS

Intratumoral CD4, CD8, and FOXP3 lymphocytes were examined by immunohistochemistry using a computer-assisted quantitative analysis in 136 PDAC patients who received neoadjuvant therapy and pancreaticoduodenectomy. The results were correlated with clinicopathological parameters and survival.

RESULTS

High CD4 TILs in treated PDAC were associated with high CD8 TILs (P = 0.003), differentiation (P = 0.04), and a lower frequency of recurrence (P = 0.02). Patients with high CD4 TILs had longer disease-free survival and overall survival (OS) than did patients with low CD4 TILs (P < 0.01). The median OS of patients with a high CD8/FOXP3 lymphocyte ratio (39.5 [standard deviation, 6.1] months) was longer than that of patients with a low CD8/FOXP3 lymphocyte ratio (28.3 [standard deviation, 2.3] months; P = 0.01). In multivariate analysis, high CD4 TILs were an independent prognostic factor for disease-free survival (hazard ratio, 0.49; 95% confidence interval, 0.30-0.81; P = 0.005) and OS (hazard ratio, 0.54; 95% confidence interval, 0.33-0.89; P = 0.02).

CONCLUSIONS

High level of CD4 lymphocytes is associated with tumor differentiation and lower recurrence and is an independent prognostic factor for survival in PDAC patients treated with neoadjuvant therapy.