Should Splenic Hilar Lymph Nodes Be Dissected For Siewert Type Ⅱ And Ⅲ Oesophagogastric Junction Carcinoma Based On Tumour Diameter?

Objective: To identify the value of a spleen-preserving No. 10 lymphadenectomy(SPL) for Siewert type Ⅱ/ⅡI adenocarcinoma of the oesophagogastric junction(AEG). Methods: From January 2007 to June 2014, 694 patients undergoing radical total gastrectomy for Siewert type Ⅱ/ⅡI AEG were analysed. Oncologic outcomes were compared between SPL and no SPL(No. 10D+ and No. 10D-) groups.Results: Of the 694 patients, 304(43.8%) had Siewert type Ⅱ AEG and 390(56.2%) had type ⅡI AEG. The mean tumour diameter was 4.9±2.2 cm, and 71.9%(499/694) of patients had a tumour diameter ≥4 cm. Thirty-six(12.3%) patients exhibited No. 10 LNM. The incidences of No. 10 LNM were 7.6% in patients with Siewert type Ⅱ AEG and 15.4% in patients with type ⅡI AEG(P=0.046). A significantly higher rate of No. 10 LNM was observed in patients with a tumour diameter ≥4 cm than with those with a tumour diameter <4 cm(17.8% vs. 1.0%, P<0.001). A stratified analysis demonstrated that there were no significant differences in No. 10 LNM for Siewert type Ⅱ AEG with tumour diameters of <4 cm and ≥4 cm(11.1% vs.2.2%, P=0.071). However, Siewert type ⅡI AEG with a tumour diameter ≥4 cm showed a significantly higher rate of No. 10 LNM compared with a tumour diameter <4 cm(21.6% vs. 0.0%, P<0.001). The No. 10D+ group had superior 3-year overall survival(OS) and disease-free survival(DFS) rates compared with the No. 10Dgroup(P=0.030 and P=0.005, respectively). For patients with Siewert type Ⅱ AEG, the 3-year OS and DFS rates were similar between the two groups. However, the No. 10D+ group showed significantly longer 3-year OS(72.9% vs. 55.1%, P=0.002) and DFS(69.8% vs. 50.4%, P<0.001) in patients with Siewert type ⅡI AEG. A stratified analysis demonstrated that for patients with Siewert type ⅡI AEG with a tumour diameter <4 cm, the 3-year OS and DFS rates were similar between the two groups.However, the No. 10D+ group had better 3-year OS(66.6% vs. 51.1%, P=0.019) and DFS(63.2% vs. 45.9%, P=0.007) rates for Siewert type ⅡI AEG with a tumour diameter ≥4 cm. A multivariate Cox regression showed that SPL was an independent prognostic factor in Siewert type ⅡI AEG with a tumour diameter ≥4 cm.Conclusions: SPL may improve the prognosis of Siewert type ⅡI AEG with a tumour diameter ≥4 cm, whereas SPL may be omitted without decreasing survival in patients with Siewert type Ⅱ or type ⅡI AEG with a tumour diameter <4 cm.