TILs IN COLORECTAL CANCER

Intratumoral tumor-infiltrating lymphocyte level and prominent peritumoral Crohn’s-like lymphoid reaction appear to be independent prognostic factors for survival in colorectal cancer, according to a study reported by Rozek et al in the Journal of the National Cancer Institute. The findings suggest that enhanced lymphocytic reaction may be associated with improved survival.

Study Details

The study involved assessment of 2,369 incident colorectal cancers from a population-based case-control study in northern Israel. Multivariate analysis for colorectal cancer–specific and overall survival included tumor-infiltrating lymphocyte level, Crohn’s-like lymphoid reaction, microsatellite instability, age, sex, ethnicity, grade, and stage. In grading Crohn’s-like lymphoid reaction, the advancing edge of the tumor was assessed for prominent inflammatory reaction, defined as a minimum of three lymphoid aggregates per section; if the advancing edge of the tumor was not present, the field was graded as unknown.

Colorectal Cancer–Specific and Overall Survival

On univariate analysis, tumors with tumor-infiltrating lymphocytes/high-powered field of ≥ 2 (26% of patients) were associated with improved colorectal cancer–specific (hazard ratio [HR] = 0.53, P < .001) and overall survival (HR = 0.75, P < .001) vs those with tumors with tumor-infiltrating lymphocytes/high-powered field < 2. Prominent Crohn’s-like lymphoid reaction (present in 33% of patients, absent in 37%) was also associated with improved colorectal cancer–specific (HR = 0.55, P < .001) and overall survival (HR = 0.69, P < .001) vs no Crohn’s-like lymphoid reaction.

On multivariate analysis, high tumor-infiltrating lymphocyte level (HR = 0.66, P < .001, for colorectal cancer–specific survival; HR = 0.76, P < .001, for overall survival) and prominent Crohn’s-like lymphoid reaction (HR = 0.65, P < .001, for colorectal cancer–specific survival; HR = 0.71, P < .001, for overall survival) but not microsatellite instability (P = .10, P = .41) remained significantly associated with survival.

The investigators concluded: “[Tumor-infiltrating lymphocytes] and [Crohn’s-like lymphoid reaction] are both prognostic indicators for [colorectal cancer] after adjusting for traditional prognostic indicators.”

The study was supported by the National Cancer Institute, the National Institutes of Health, and the Anton B. Burg Foundation.

Stephen B. Gruber, MD, PhD, of the USC Norris Comprehensive Cancer Center, is the corresponding author of the Journal of the National Cancer Institute article.