Impact of macroscopic enlarged lymph node on stage II colorectal cancer prognosis and its potential mechanism

Abstract

To evaluate the impact of macroscopic enlarged lymph node on the clinicopathological characteristics of stage II colorectal cancer, and to explore the potential mechanism. Clinicopathological data of 116 consecutive patients with stage II colorectal cancer, who underwent colorectal radical resection and were identified as stage II colorectal cancer without mesenteric metastasis by postoperative pathology, in our department between December 2001 and December 2002 were analyzed retrospectively. All the patients were examined by the surgeons with gross appearance to decide the enlarged lymph nodes as metastasis during operation. There were 43 patients with macroscopic enlarged lymph nodes and 73 without such lymph nodes. Survival rate was compared between the two groups. Impact of macroscopic enlarged lymph node on the prognosis of stage II colorectal cancer was analyzed. Structure of macroscopic enlarged lymph node was observed. CK expression in 107 macroscopic enlarged lymph nodes from 43 cases was examined by immunohistochemistry. The 10-year disease-free survival (DFS) of the whole group was 83.5%. The 10-year DFS of patients with macroscopic enlarged lymph nodes was 75.9%, which was significantly lower than 89.3% (P=0.038) of patients without macroscopic enlarged lymph nodes. Univariate analysis showed that macroscopical enlarged lymph node (P=0.038), perioperative blood transfusion (P=0.004), number of retrieved lymph nodes (P=0.016), concomitant disease (P=0.003), and preoperative serum carcinoembryonic antigen (CEA) level (P=0.050) were related to the prognosis of all the 116 patients. Multivariate analysis showed that macroscopical enlarged lymph node (P=0.044), number of retrieved lymph nodes (P=0.021), and perioperative blood transfusion (P=0.032) were independent prognostic factors. Haematoxylin and eosin (HE) staining indicated that enlarged lymph nodes had hyperplasia reaction. Immunohistochemistry showed that among 107 enlarged lymph nodes, 1 had macrometastases, 1 micrometastasis, 4 isolated tumor cell (ITC), and the rest 101 had no positive CK expression. Macroscopic enlarged lymph node indicates a poor prognosis in patients with stage II colorectal cancer.