Clinical implications of intratumoral dendritic cell infiltration in esophageal squamous cell carcinoma

The clinical impact of intratumoral dendritic cell infiltration (IDCI) in esophageal cancer is not fully understood. We investigated the relationship between IDCI and clinical features in esophageal carcinoma. A retrospective analysis of a total of 203 patients who underwent esophagectomy for squamous cell esophageal carcinoma was performed. We evaluated IDCI immunohistochemically using S-100-protein. Under a high power objective (x400), we evaluated IDCI in 10 regions of surgical specimen including the most invasive slice and averaged the number of S-100-protein positive cells. The patients were classified into two groups according to IDCI (>20 or <20 S-100-protein positive cells per high power field: high or low IDCI, respectively). The degree of IDCI varied from 0 to 67 (average 12.3). The 203 patients were separated into 65 with high IDCI and 138 with low IDCI. The depth of invasion was significantly more superficial in patients with high IDCI (p<0.05), and the disease was at an earlier clinical stage (p<0.01) than in those with low IDCI. Five-year survival rates after curative resection were 67% and 39% in patients with high and low IDCI, respectively (p<0.01). Multivariate analysis showed that IDCI was an independent prognostic factor (RR=1.6, p=0.02), next to nodal involvement, depth of invasion and clinical stage. Being closely related to clinical features, the prognosis of patients with esophageal cancer may be estimated by monitoring IDCI.