Is No. 12a Lymph Node Dissection Compliance Necessary in Patients Who Undergo D2 Gastrectomy for Gastric Adenocarcinomas? A Population-Based Retrospective Propensity Score Matching Study

SIMPLE SUMMARY: Since nodal metastasis is the main pattern for gastric cancer (GC) metastasis, lymph node (LN) dissection is essential for accurate staging and improving prognosis. However, debates exist regarding the necessity of No. 12a LN dissection (LND) in D2 gastrectomy. Moreover, the compliance rate for No. 12a LND in practice is low. To explore No. 12a LND noncompliance’s effect on long-term prognosis in GC patients after D2 gastrectomy, we performed a retrospective propensity score matching study with 2788 patients included. The results showed that patients with No. 12a LND had a significantly greater OS than those without it before and after PSM. This study is the first propensity score matching study to demonstrate the prognostic impact of No. 12a LND noncompliance on patients who undergo D2 gastrectomy. This large population-based study may provide guidance on No. 12a LND. ABSTRACT: LN dissection is essential for accurately staging and improving GC patient prognosis. However, the compliance rate for No. 12a LND in practice is low, and its necessity is controversial. Data from GC patients who underwent total gastrectomy (TG)/distal gastrectomy (DG) plus D2 lymphadenectomy between January 2000 and December 2017 at West China Hospital, Sichuan University were reviewed. No. 12a LND noncompliance’s effect on the long-term prognosis of patients with GC after D2 gastrectomy was explored. Of the 2788 patients included, No. 12a LND noncompliance occurred in 1753 patients (62.9%). Among 1035 patients with assessable LNs from station 12a, 98 (9.5%) had positive LNs detected at station 12a. No. 12a LN metastasis patients (stage IV not included) had significantly better overall survival (OS) than TNM stage IV patients (p = 0.006). Patients with No. 12a LND compliance had a significantly higher OS than those without, both before (p < 0.001) and after (p < 0.001) PSM. Cox multivariate analysis confirmed that No. 12a LND noncompliance was an independent prognostic factor before (HR 1.323, 95% CI 1.171–1.496, p < 0.001) and after (HR 1.353, 95% CI 1.173–1.560, p < 0.001) PSM. In conclusion, noncompliance with No. 12a LND compromised the long-term survival of patients who underwent D2 gastrectomy for GC.