Defining Optimal Lymph Node Yield in Gastrectomy: A Real-World Cohort Analysis.

BACKGROUND

Gastric cancer (GC) has a high global mortality and incidence rate. Lymph node (LN) invasion is crucial in TNM staging, and an accurate LN staging system is vital for treatment decisions. However, the appropriate number of examined LNs remains uncertain.

METHODS

We retrospectively analyzed consecutive GC patients who underwent gastrectomy at the First Medical Center of the Chinese PLA General Hospital from January 2010 to December 2023. A new statistical model based on the β-binomial distribution and maximum likelihood method in R software was employed to calculate false-negative probabilities.

RESULTS

A total of 6463 GC patients were included. For cT1 patients, even with only five LNs excised, the likelihood of encountering occult positive LNs remained below 5%. For cT2 patients, 17 nodes were needed to rule out occult nodal disease with 90% confidence. While for cT3 and cT4 patients, even after the removal of 35 LNs, the likelihood of overlooking a positive node was still above 20%. Considering surgical extent, 25 nodes were required for patients who underwent proximal gastrectomy or distal gastrectomy to rule out occult nodal disease with 90% confidence, whereas those who received entire gastrectomy needed 59 nodes to achieve the same level of confidence.

CONCLUSION

Our study establishes a novel quantitative framework linking LN harvest thresholds to false-negative metastasis risk in GC, derived from real-world clinicopathological data.