Density of Tumor-Infiltrating Lymphocytes Correlates with Disease Recurrence and Survival in Patients with Large Non-Small-Cell Lung Cancer Tumors

Background The density of tumor-infiltrating lymphocytes (TIL) in lung cancer is variable and may have an impact on disease course. We reviewed the histology of lobectomy specimens from patients with pathologic stage IA-IB non-small-cell lung cancer to determine the impact of TILs on recurrence and survival. Materials and methods Two hundred nineteen lobectomies performed between 2002 and 2005 for stage IA-IB non-small-cell lung cancer were reviewed. Patients were stratified according to tumor size. Infiltrating patterns were graded as follows: group 1 (none to mild infiltrate) or group 2 (moderate to severe infiltrate). Recurrence rates and disease-free survival were compared between groups in each tumor size cohort. Results A higher density of TILs was associated with lower disease recurrence (60%, group 1 versus 21%, group 2, P = 0.02) and improved 5-y disease-free survival (35.9%, group 1 versus 75.6%, group 2, P = 0.04) in patients with tumors 5cm or greater in diameter. There were no correlations in patients with smaller tumors. Conclusions A higher degree of TILs within large node-negative non-small-cell lung cancer correlates with decreased risk of disease recurrence and improved disease-free survival. This subset of patients with tumor infiltration needs to be examined more closely with regards to outcomes of adjuvant chemotherapy.