Regional Lymph Nodes Status and Ratio of Metastatic to Examined Lymph Nodes Correlate with Survival in Stage IV Colorectal Cancer.

Abstract

Although lymph nodes status and the ratio of metastatic to examined lymph node (LNR) are important prognostic factors in early-stage colorectal cancer (CRC), their significance in patients with metastatic disease remains unknown. The study aims to determine prognostic importance of nodal status and LNR in patients with stage IV CRC. A cohort of 1109 eligible patients who were diagnosed with synchronous metastatic CRC in Saskatchewan during 1992-2010 and underwent primary tumor resection was evaluated. We conducted the Cox proportional multivariate analyses to determine the prognostic significance of nodal status and LNR. Median age was 70years (22-98) and M:F was 1.2:1. Rectal cancer was found in 26% of patients; 96% had T3/T4 tumor, and 82% had node positive disease. The median LNR was 0.36 (0-1.0). Fifty-four percent received chemotherapy. Median overall survival of patients who had LNR of <0.36 and received chemotherapy was 29.7months (95% CI 26.6-32.9) compared with 15.6months (95% CI 13.6-17.6) with LNR of ≥0.36 (P<.001). On multivariate analyses, no chemotherapy (HR 2.36 [2.0-2.79]), not having metastasectomy (HR 1.94 [1.63-2.32]), LNR ≥0.36 (HR 1.59 [1.38-1.84]). nodal status (HR 1.34 [1.14-1.59]), and T status (HR 1.23 [1.07-1.40]) were correlated with survival. Test for interaction was positive for LNR and high-grade cancer (HR 1.51 [1.10-2.10]). Our results suggest that nodal status and LNR are important prognostic factors independent of chemotherapy and metastasectomy in stage IV CRC patients.