Lymph Node Metastasis Frequency and Development of Predictive Model in T1b Gastric Cancer: A Single-Center Study

Area of Science:

• Gastroenterology
• Surgical Oncology
• Pathology

Background:

• Optimal management of T1b gastric cancer (GC) is debated due to lymph node metastasis (LNM) risk.
• Understanding LNM distribution is crucial for treatment strategies in T1b GC.

Purpose of the Study:

• To clarify the anatomical distribution of LNM in T1b GC.
• To develop a predictive nomogram for LNM in T1b GC patients.

Main Methods:

• Retrospective analysis of 1041 T1b GC patients undergoing D2 gastrectomy.
• Assessment of LNM frequency, distribution, and skip metastases.
• Development and validation of a predictive nomogram using logistic regression and ROC curves.

Main Results:

• Overall LNM incidence was 28.34%, with heterogeneous distribution.
• No LNM in well-differentiated tumors ≤ 3 cm; limited to first-tier nodes in moderately to well-differentiated tumors of this size.
• Independent predictors included female sex, younger age, larger tumor size, poor differentiation, and lymphovascular invasion; nomogram showed good discrimination (AUC 0.83).

Conclusions:

• LNM in T1b GC is heterogeneous and not predictable by anatomical site alone.
• Sentinel lymph node biopsy may suit selected T1b GC patients (≤ 3 cm, moderate-to-well differentiated).
• The nomogram aids individualized surgical decisions for T1b GC, pending external validation.