Predictors of nodal positivity in clinically under-staged patients with colon cancer: A National Cancer Database study and proposal of a predictive scoring system

Background: Colon cancer pathological and clinical staging may be disoncordant. This study assessed patients with colon cancer in whom the nodal status was clinically understaged. Methods: Patients with stage I-III clinical node-negative colon cancer from the National Cancer Database were included. Regression analyses were conducted to elucidate risk factors for clinical nodal understaging and a scoring system was developed to identify high-risk patients. Results: The study included 94,945 patients with 78.4 % of patients correctly staged and 21.6 % clinically understaged. The predictors of nodal positivity in clinically understaged patients were age <65 (OR 1.43), left-sided tumors (OR 1.41), elevated CEA (OR 2.03), moderately (OR 1.81) or poorly/undifferentiated tumors (OR 3.76), T1 tumors (OR 1.29), signet-ring cell histology (OR 2.26), and microsatellite-stable tumors (OR 1.4). Conclusion: Patients with colon cancer and the above factors are more likely to have their nodal status clinically understaged. A scoring system has been developed to identify high-risk patients.