Extranodal metastasis predicts poor survival in advanced colorectal cancer

The prognostic significance of extranodal metastasis (ENM) in colorectal cancer (CRC) is disregarded by the TNM classification system. The influence of ENM on survival among locally advanced CRC patients was examined.

We reviewed retrospectively the clinical course of 263 patients who underwent surgical resection of locally advanced CRC at our Department between 2005 and 2009. We analyzed the prognostic factors with special reference to the clinicopathological factors of primary tumors.

Thirty-eight cases of ENM were detected among patients with CRC. Compared with ENM negative cancers, ENM-positive cancers were associated with poorer tumor differentiation grade (p=0.026) and higher prevalence of TNM-stage (p<0.0001), T-status (p=0.024), N-status (p<0.0001) and postoperative recurrence (p<0.0001). In univariate analysis, TNM-stage (p<0.0035), T-status (p=0.002), N-status (p<0.0024) and positive ENM (p<0.0001) were significant predictors of poor survival. Multivariate analyses showed a positive ENM to be a highly significant independent predictor of mortality (HR=1.98, 95% CI=1.23- 3.23, p=0.0053). Survival analyses using Kaplan-Meier curves demonstrated that patients with ENM-positive cancers had significantly poorer survival than patients with ENM-negative cancers. Patients with ENM-negative cancers did not show significantly different survival from patients with node-negative cancers (p=0.272, data not shown).

ENM appears to be a strong independent negative prognostic factor of poor survival in locally advanced CRC.