Analysis of the risk factor of insufficient examined lymph nodes in stage II colon cancer from the perspective of stage migration: A retrospective study combined with external validation.

BACKGROUND

An insufficient examined lymph node (ELN) count is a high risk factor for recurrence in patients with stage II colon cancer (CC). This study aimed to explore this risk factor in relation to stage migration.

METHODS

We screened 18,544 patients with stage II (pT3/4N0M0) and IIIB (pT3/4N1M0) CC diagnosed after radical resection from 2010 to 2015, using the National Cancer Institute Surveillance, Epidemiology, and End Results database. Propensity score matching was used to balance confounding factors for short-term and long-term survival, and survival analysis was carried out using the Kaplan-Meier method and log-rank test. The optimal cutoff for the number of ELNs in patients with stage II CC was determined using X-tile software. Independent prognostic factors were screened using Cox proportional hazards regression analysis. Finally, the results were externally validated in 318 patients with stage Ⅱ and ⅢB CC in our hospital from 2013 to 2015.

RESULTS

The best cutoff value for the number of ELNs in patients with stage II CC was 14. Multivariate analysis identified age, grade, histology, tumor size, T stage, N stage, ELN count, and chemotherapy as independent prognostic factors, and the Akaike and Bayesian information criteria values for the prognostic value of ELN count were relatively small. Patients with stage II CC with <15 ELNs had similar prognoses to patients with stage ⅢB CC (P = 0.939). Subgroup analysis and external validation yielded similar results.

CONCLUSION

Patients with stage II CC should be considered as stage ⅢB if the ELN count is insufficient.