The prognostic role of para-aortic lymph nodes in patients with colorectal cancer: Is it regional or distant disease?

Abstract

Introduction: Visible para-aortic lymph nodes of ≥2 mm in size are common metastatic patterns of colorectal cancer (CRC) seen on imaging. Their prognostic value, however, remains inconclusive. We aimed to assess the prognostic role of visible para-aortic lymph nodes (PALNs). Methods: Patients with confirmed pathologic diagnosis of CRC were enrolled. Correlations among clinicopathologic variables were analyzed using the χ 2 test. The Cox proportional hazards model was applied for univariate and multivariate analyses. Survival was estimated using the Kaplan-Meier method and log-rank test. A prognostic model for visible PALNs in CRC patients was established. Results: In total, 4527 newly diagnosed CRC patients were enrolled. Patients with visible PALNs had inferior overall survival compared to those without visible PALNs (5-year overall survival, 67% vs. 76%, P = 0.015). Lymphovascular invasion (LVI) (hazard ratio = 1.865, P = 0.015); nodal disease (pN+) status (hazard ratio = 2.099, P = 0.006); elevated preoperative serum carcinoembryonic antigen (CEA) levels (hazard ratio = 2.263, P < 0.001); and visible PALNs ≥10 mm (hazard ratio = 1.638, P = 0.031) were independent prognostic factors for patients with visible PALNs. If each prognostic factor scored one point, 5-year overall survival of lower- (prognostic score 0-1), intermediate- (prognostic score 2), and high- (prognostic score 3-4) risk groups were, 78%. 54%, and 25% respectively (P < 0.001). Conclusions: The prognostic model, which included LVI, pN+ status, preoperative serum CEA level, and the size of visible PALNs, could effectively distinguish the outcome of patients with visible PALNs.