E477: Lymphadenectomy for Gastric Cancer in the FLOT Era: Analysis of the National Cancer Database

Introduction: The management of locally advanced gastric cancer has evolved rapidly with the establishment of fluorouracil, leucovorin, oxaliplatin, docetaxel (FLOT) as a standard perioperative systemic therapy and the adoption of minimally-invasive surgical techniques. We analyzed the rate of adequate lymphadenectomy (≥15 lymph nodes) during this “modern era” of gastric cancer management.

Methods: Patients with clinically non-metastatic (Stage 1-4a) gastric cancer who received neoadjuvant systemic therapy since the introduction of FLOT in 2019 were identified in the National Cancer Database, and trends of adequate lymphadenectomy were analyzed. Multivariable logistic regression modeling (MVR) was employed to identify factors associated with adequate lymphadenectomy. We analyzed the association of age, sex, race, Charlson index, insurance type, income, treatment setting (Academic vs Community Hospital, >500 vs 100-500 cases per year), clinical stage, and surgical approach (open vs laparoscopic vs robotic-assisted) with MVR. Cox regression modeling was utilized to assess differences in overall survival between cohorts.

Results:
A total of 1,572 eligible patients were included in the analysis, and 1,339 (85.2%) had an adequate lymphadenectomy. Of the 1,258 patients with complete surgical approach data, 666 (52.9%) had open surgery, 344 (27.3%) had laparoscopic surgery, and 248 (19.7%) had robotic-assisted surgery. MVR showed that private insurance was associated with increased rate of adequate lymphadenectomy (OR 1.81, 95% CI 1.05-3.11) compared to other insurance types, and that compared to Stage 1, Stage 2 (OR 1.75, 95% CI 1.10-2.76) and Stage 3 (OR 2.3, 95% CI 1.42-3.77) were associated with increased rate of adequate lymphadenectomy. Age, sex, race, income, treatment setting, and surgical approach were not associated with adequate lymphadenectomy. Rates of adequate lymphadenectomy were similar in open, laparoscopic, and robotic-assisted groups: 83.7%, 84.6%, and 86.3% respectively. There was no difference in 1-year overall survival between patients with inadequate and adequate lymphadenectomy (88.8% vs 93.9%, p=0.218).


Conclusions:
This study suggests that since the introduction of FLOT chemotherapy and adoption of minimally invasive techniques, most patients with gastric cancer undergo adequate lymphadenectomy. Increasing clinical stage and private insurance were associated with higher rates of adequate lymphadenectomy. Further investigation, focusing on the potential impact of lymphadenectomy on survival in the FLOT era, will be revealing with longer follow-up.