The minimum number of lymph node retrieval in gastric cancer patients after neoadjuvant therapy: An international multi-institute cohort study.

BACKGROUND

The minimum number of retrieved lymph nodes for radical gastrectomy after neoadjuvant therapy remains controversial. The objective of this study was to determine the minimum threshold for retrieved lymph nodes in patients with gastric cancer after neoadjuvant therapy to accurately evaluate staging and prognosis.

METHODS

Multivariate models were employed to investigate the correlation between the number of retrieved lymph nodes and survival outcomes and stage migration. The hazard ratio curves for each retrieved lymph node count compared with 1 retrieved lymph node (as a reference), including overall survival and disease-specific survival, were fitted using a LOWESS smoother, and the structural break points were determined by Chow test.

RESULTS

This international multicenter study analyzed the clinicopathological data of 2,490 patients with gastric cancer who underwent gastrectomy after neoadjuvant therapy. The median follow-up period for the overall population was 90.0 months, with a median of 22 retrieved lymph nodes. The study demonstrated that a greater number of retrieved lymph nodes was linked to a greater probability of detecting positive lymph nodes (odds ratio, 1.005; P = .030) as well as improved overall survival and disease-specific survival (overall survival: hazard ratio, 0.988; P < .001 and disease-specific survival: hazard ratio, 0.987; P < .001). The cutoff point analysis identified 24 as the minimum number of retrieved lymph nodes. The 5-year overall survival rate was significantly greater in the group with ≥24 retrieved lymph nodes (46.0%) compared with the group with 16-23 retrieved lymph nodes (35.3%) and the group with <16 retrieved lymph nodes group (29.3%) (P < .001). Similar trends were observed with regard to disease-specific survival. The time-dependent area under the curve analysis revealed that the group with ≥24 retrieved lymph nodes exhibited superior predictive performance for overall survival and disease-specific survival compared to the group with <24 retrieved lymph nodes, on the basis of ypN staging (overall survival: time-dependent areas under the receiver operating characteristic curve, 0.71 vs time-dependent areas under the receiver operating characteristic curve, 0.67; disease-specific survival: time-dependent areas under the receiver operating characteristic curve, 0.72 vs time-dependent areas under the receiver operating characteristic curve, 0.68).

CONCLUSION

The minimum number of retrieved lymph nodes for evaluation prognosis and reducing stage migration in patients with gastric cancer who undergo radical gastrectomy after neoadjuvant therapy was 24.