Tailored minimum examined lymph node threshold for colon cancer from large multi database analysis

The optimal number of examined lymph nodes (ELNs) for colon cancer (CC) remains controversial. This study aims to identify patient-specific factors associated with the number of ELNs retrieved in CC patients undergoing hemicolectomy and to explore the potential for establishing a minimum ELNs threshold based on patient characteristics. We retrospectively analyzed data on patients with stage I-III CC from two sources: the Chinese Multi-Institutional Registry (CMIR, N = 10,367; 2010–2018) and the Surveillance, Epidemiology, and End. Results (SEER) database (N = 121,216; 2010–2018). Logistic regression modeling was used to identify patient-specific factors associated with ELN counts. Eight distinct patient cohorts were constructed, and the relationship between ELNs and overall survival (OS) was assessed using restricted cubic spline (RCS) curves and Kaplan-Meier curves. This study was registered with the ChiCT Registry (ChiCTR2400084767). The median ELN count was 16 (IQR 12–22) in the SEER cohort and 15 (IQR 12–20) in the Chinese cohort. Age, tumor size, and location emerged as key factors influencing ELN numbers. Notably, the optimal ELN thresholds for optimal survival across all eight cohorts ranged from 14 to 17, exceeding the current recommendation of 12. Exceeding these cohort-specific thresholds was associated with significantly improved OS in both databases (all P < 0.001). The detailed comparison of ELN-related statistics between the two databases is shown in Supplementary Table X. The present study reveals heterogeneity in the minimum ELN requirements across different patient cohorts with CC. Further prospective studies and randomized controlled trials are warranted to validate these tailored thresholds and inform guideline updates.