Tumor infiltrating lymphocytes (TIL), which represent host adaptive response to the tumor, were first identified at scanning magnification to select areas with the highest counts on hematoxylin and eosin slides, quantitated per high-power field (HPF), and analyzed for association with recurrence-free survival (RFS) in 848 patients. Highest TIL in a single HPF was analyzed as a continuous and categorical variable, and optimal cutoff analysis was performed to predict RFS. Highest TIL count in a single HPF ranged from 0 to 45, and the optimal cutoff for TIL high vs TIL low was determined to be ≥ 3 vs < 3 with a concordance probability estimate of 0.74. In the entire cohort, 5-year RFS was 90.2% (95% CI = 83.7–94.2) in TIL high compared to 78.9% (95% CI = 74.1–82.9) in TIL low (log rank P