The prognostic value of log odds of positive lymph nodes in patients with resectable locally advanced gastric cancer following neoadjuvant therapy: results from the SEER database.

BACKGROUND

Lymph node status is a critical prognostic factor for locally advanced gastric cancer (LAGC), but the comparative value of different lymph node metrics after neoadjuvant chemotherapy (NACT) remains unclear. This study aims to evaluate and compare the prognostic utility of positive lymph nodes (pLNs), lymph node ratio (LNR), and the log odds of positive lymph nodes (LODDS) in patients with LAGC undergoing radical gastrectomy after NACT.

METHODS

A total of 1,976 patients from the Surveillance, Epidemiology, and End Results (SEER) database and a propensity score-matched (PSM) validation cohort of 69 Chinese patients were analyzed. A NACT-only subgroup (n=658) was evaluated to exclude radiotherapy effects. Prognostic value was assessed via Cox models, Kaplan-Meier curves, concordance indices (C-indices), and time-dependent receiver operating characteristic (ROC) analyses.

RESULTS

In the SEER cohort, LODDS >-2.02 and LNR >0.12 showed comparable hazard ratios (HRs) for overall survival (OS) and cancer-specific survival (CSS), both outperforming pLNs. LODDS demonstrated the highest prognostic accuracy (OS: C-index 0.671; CSS: 0.690). In the NACT-only subgroup, LODDS remained the strongest predictor (OS: HR =3.34; CSS: HR =3.69) with superior C-indices (OS: 0.718; CSS: 0.730). An independent Chinese validation cohort (n=69) preliminarily supported LODDS' prognostic strength (multivariable OS: HR =20.61, P=0.008; CSS: HR =14.58, P=0.02).

CONCLUSIONS

LODDS provides modest but robust and supplementary prognostic value in LAGC patients treated with neoadjuvant therapy. Its integration into existing staging systems may enhance individualized risk stratification and guide clinical decision-making.