Immune Cell Infiltrate and Prognosis in Gastric Cancer.

Purpose: To examine and compare the prognostic value of immune cell score (ICS) and Klintrup-Mäkinen (KM) grade in gastric cancer.
Methods: Gastric adenocarcinoma tissues from samples of 741 patients surgically treated in two hospitals in Finland were assessed for ICS and KM grade. Cox regression with adjustment for confounders provided hazard ratios (HRs) and 95% CIs. Subgroup analyses were performed in intestinal and diffuse type subgroups. The primary outcome was 5-year overall survival.
Results: High ICS was associated to longer 5-year survival (adjusted HR 0.70, 95% CI 0.52-0.94), compared to low ICS. The difference was significant in intestinal type subgroup (adjusted HR 0.54, 95% CI 0.36-0.81) but not in diffuse type subgroup (adjusted HR 0.92, 95% CI 0.58-1.46). High KM grade was an independent prognostic factor for longer 5-year overall survival (adjusted HR 0.59, 95% CI 0.45-0.77) in both intestinal (adjusted HR 0.61, 95% CI 0.44-0.85) and diffuse subgroups (adjusted HR 0.52, 95% CI 0.31-0.86). ICS and KM grade were moderately correlated (ρ = 0.425). When both immune cell score and KM grade were included in the regression analysis, only KM grade remained prognostic.
Conclusions: Both ICS and KM grade are prognostic factors in gastric adenocarcinoma, but immunohistochemistry-based ICS might not have additional prognostic value over hematoxylin-eosin-based KM grade.