Clinical significance of lower perigastric lymph nodes dissection in Siewert type II/III adenocarcinoma of esophagogastric junction: a retrospective propensity score matched study

The optimal surgical procedure, whether total gastrectomy (TG) or proximal gastrectomy (PG), for Siewert type II/III adenocarcinoma of esophagogastric junction (AEG) has not been standardised, primarily because the optimal extent of lymph node (LN) dissection for AEG based on the metastatic rate of perigastric LNs remains under debate. The aim of this study was to investigate the metastatic incidence and prognostic significance of lower perigastric lymph nodes (LPLN), including No.4d, 5, 6 and 12a LN stations, in Siewert type II/III AEG.A total of 701 patients with Siewert type II/III AEG who received transabdominal open gastrectomy (425 patients with TG and 276 patients with PG) from 2010 to 2015 in West China Hospital were retrospectively included. Based on the clinicopathological information of TG patients, the risk factors of LPLN-positive patients were evaluated, and the metastatic incidence as well as the therapeutic value (TV) index of each LN station was assessed. Moreover, the 5-year overall survival (OS) rates between LPLN-positive and LPLN-negative groups were compared in TG patients, and the postoperative survival difference between TG and PG patients was also compared, using propensity score matching (PSM) method.Tumour size (≥ 5 cm, OR = 1.481, p = 0.002) and pT stage (pT4, OR = 2.755, p = 0.024) were significant risk factors for patients with LPLN metastasis. For patients with tumour size more than 5 cm or pT4 stage, the metastatic rates of LPLN for Siewert type II, III and II/III AEG were 31.67%, 34.69% and 33.03%, whereas the TV indexes of LPLN for them were 5.76, 5.62 and 5.38, respectively. LPLN was a significant independent prognostic factor (HR = 1.422, p = 0.028), and positive LPLN was related to worse prognosis (p < 0.05). For patients with tumour size more than 5 cm or pT4 stage, TG patients were illustrated to have a better prognosis than PG patients, with 5-year OS rates of 58.9% vs 38.2% for Siewert type II AEG (χ2 = 4.159, p = 0.041), 68.9% vs 50.2% for Siewert type III AEG (χ2 = 5.630, p = 0.018) and 65.1% vs 40.3% for Siewert type II/III AEG (χ2 = 12.604, p < 0.001), respectively.LPLN metastasis is a poor prognostic factor for patients with Siewert II/III AEG. LPLN dissection may improve the long-term survival of patients with tumour size more than 5 cm or pT4 stage, and TG might be more suitable for this kind of cancer.