Prognostic Impact of Lymph Node Ratio in Patients With Gastric Cancer Undergoing Curative Gastrectomy Post...

The lymph node ratio (LNR), defined as the ratio of metastatic to examined lymph nodes, is a prognostic indicator in gastric cancer after curative gastrectomy. However, in response to neoadjuvant chemotherapy (NAC), the absolute number of metastatic lymph nodes may decrease. Moreover, the N-stage classification after this (ypN) alone may not fully reflect residual nodal disease. We evaluated whether LNR-based stratification offers improved prognostic discrimination compared with ypN classification, using survival analysis together with time-dependent receiver operating characteristics analysis.

We retrospectively analyzed 201 patients with gastric adenocarcinoma who underwent post-NAC curative (R0) gastrectomy with D2 lymphadenectomy at Kanagawa Cancer Center (March 1992 to November 2019). Patients were classified using commonly reported LNR cutoffs: low (<0.10), intermediate (0.10-0.25), and high (>0.25). Recurrence-free (RFS) and overall survival (OS) were evaluated. The prognostic performance of the LNR and the ypN classification was compared using multivariate Cox proportional hazards models.

The median follow-up period was 37.6 months. Higher LNR was associated with worse RFS and OS (p<0.001, global log-rank test). Unlike yPN, LNR remained an independent adverse prognostic factor for RFS [hazard ratio (95% confidence interval) vs. low LNR: intermediate: 3.622 (1.302-10.08), p=0.017; high: 3.923 (1.154-13.34), p=0.029] and OS [vs. low LNR: intermediate: 3.590 (1.341-9.606), p=0.011; high: 4.057 (1.230-13.38), p=0.021] in multivariate analysis.

The LNR may serve as a practical postoperative risk stratification metric for recurrence and survival after NAC in patients with gastric cancer, complementing the limitations of the ypN classification.