Prognostic value of regional lymph node ratio (LNR) in locally advanced gastric cancer: A single center analysis.

Abstract

448 Background: Objective: to evaluate the relationship between the ratio of metastatic regional lymph nodes (LN) in locally advanced gastric cancer and survival in patients who underwent perioperative therapy and radical surgery for GC. Methods: We observed 210 patients with verified locally advanced gastric cancer who received treatment in St. Petersburg City Clinical Oncology Dispensary from 2020 to 2023.The study cohort of patients included 117 (55.7%) women and 93 men (44.3%), aged from 28 to 81 years, the median age was 64.0 years [58.0-70.0]. Regional LN - cN0 was in most patients 107 (51.0%) (p=0.0016). All patients received NACT: 125 pp. (59.4%) - FLOT, 85 pp. (40.5%) - FOLFOX (p=0.0001). Median of NACT cycles was 4 [4-4]. After NACT, all patients underwent surgery. Complete therapeutic pathomorphosis by Mandard (TRG1) was in 19 (9.1%), TRG2 in 32 (15.3%), TRG3 in 62 (29.7%), TRG4 in 80 (38.8%) and TRG5 in 16 (7.7%) samples. Results: We assessed the number of examined lymph nodes (LN), the number of affected lymph nodes, and calculated the ratio of affected to examined LN, multiplied by 100 - the LN ratio (LNR). The number of examined LN varied from 1-61, the median of examined LN was 24 [19-30]. The number of affected LN varied from 0 to 20, the median was 0 [0-2]. The LNR varied from 0 to 300, the median was 0 [0-10.7]. Using ROC analysis and the Yoden index, the optimal cut-off of the LNR was determined, which has a significant impact on the PFS of patients >7.14. The median PFS of patients with LNR index exceeding 7.14 was 13.0 months (95% CI 10.0-24.0), which was significantly less than the median PFS of those patients whose LNR did not exceed the threshold of 7.14 and was not reached at the data cutoff (p<0.0001; OR 0.09 (95% CI 0.05-0.18). The median OS in patients whose LNR index did not exceed the threshold at the data cutoff was also not reached and significantly exceeded the median OS in the group of patients whose LNR index exceeded 7.14, where it was 48.0 months (36.0-50.0) (p<0.00001; OR 0.11 95% CI 0.04-0.32). When conducting a multivariate analysis using proportional hazards assessment Cox, a significant (p=0.0082) model was obtained, and the negative prognostic factors that increase the risk of progression of patients with locally advanced gastric cancer were ypT2-3 (p=0.0488), ypN2-3 (p=0.0220) and the LNR level>7.14 (p=0.0059). Conclusions: Our study showed that a high LNR index (>7.14) was significantly associated with worse recurrence-free and overall survival in patients who underwent perioperative chemotherapy and radical gastrectomy. The ratio of metastatic regional lymph nodes (LNR) can be used as an independent prognostic factor in patients with resectable GC.