Prognostic Value of the N1c in Stage III and IV Colorectal Cancer: A Propensity Score Matching Study Based on the Surveillance, Epidemiology, and End Results (SEER) Database.

The prognostic role of the N1c remains unclear in colorectal cancer (CRC). Our study aimed to determine the prognostic value of N1c. Patients diagnosed in 2010-2015 were accessed from the Surveillance, Epidemiology, and End Results (SEER) database. COX univariate and multivariate regression analysis and the Kaplan-Meier method were used to assess the impact of the N1c stage on the cause-specific (CSS) and overall survival (OS). Propensity score matching (PSM) was used to construct a matched group with similar propensity scores. Kaplan-Meier analysis showed that the CSS and OS rates in N1a were significantly better than N1c in stage III and IV CRCs after reducing selection bias (CSS: P < 0.001 in stage III, P = 0.041 in stage IV; OS: P < 0.001 in stage III, P = 0.0079 in stage IV). There were no statistical differences in CSS and OS between N1b and N1c (CSS: P = 0.500 in stage III, P = 0.270 in stage IV; OS: P = 0.390 in stage III, P = 0.600 in stage IV). Further, the prognostic value of N1c with only one tumor deposit (TD) is equivalent to N1a based on the comparison of CSS and OS rates (CSS: P = 0.420; OS: P = 0.310). Whereas N1c with only one TD had significantly better CSS and OS than N1b (CSS: P = 0.039; OS: P = 0.037). The CSS and OS rates of N1c do not achieve a statistical difference with N1b in both stage III and IV CRCs. Significantly, higher CSS and OS rates were found in N1c with only one TD versus N1b stage in stage III CRC.