Application value of splenic hilar lymphadenectomy in patients with Siewert type〖JP〗 Ⅱ and Ⅲ adenocarcinoma of esophagogastric junction and a tumor diameter≥4 cm

Objective:To investigate the longterm outcomes of splenic hilar lymphadenectomy (SPL) in patients with Siewert type Ⅱ and Ⅲ adenocarcinoma of esophagogastric junction (AEG) and a tumor diameter≥ 4 cm after radical total gastrectomy.
Methods：The retrospectively cohort study was conducted. The clinicopathological data of 412 patients with Siewert type Ⅱ and Ⅲ AEG and a tumor diameter≥4 cm who were admitted to the Fujian Medical University Union Hospital from December 2007 to December 2013 were collected. Transabdominal and open or laparoscopic radical total gastrectomies were applied to 412 patients by surgeons in the same team. Of 412 patients, 154 receiving spleenpreserving SPL in situ were allocated into the SPL group and 258 who didn′t receive SPL were allocated into the nonSPL group. Observation indicators included: (1) surgical situations, (2) followup situations, (3) postoperative survival factors analysis in patients with Siewert type Ⅲ AEG and a tumor diameter≥4 cm. Followup using outpatient examination, doortodoor visit, correspondence and telephone interview was performed once every 3 months within 2 years postoperatively and once every 6 months within 3-5 years postoperatively up to June 2015. Followup included regular physical examination, laboratory examinations (levels of CA19-9, CA72-4 and CEA), chest Xray, total abdomen color Doppler ultrasonography or computed tomography (CT) scan and annual gastroscopy. The overall survival was from operation to the last followup or death or deadline of followup database (loss to followup and dying of other diseases). Measurement data with normal distribution were represented as ±s and comparison between groups was analyzed using the t test. Measurement data with skewed distribution were described as M (range) and comparison between groups was analyzed using the MannWhitney U test. Count data were analyzed using the chisquare test or Fisher exact probability. The survival rate and survival comparison were respectively done by the KaplanMeier method and the Logrank test. The univariate analysis and multivariate analysis were done using the chisquare test and COX regression model.
Results：(1) Surgical situations: operation time, volume of intraoperative blood loss and number of lymph node dissected were (217±65)minutes, 50 mL (range, 10-1 000 mL), 38±13 in the SPL group and (204± 54)minutes, 50 mL (range, 5-2 000 mL), 31±10 in the nonSPL group, respectively, with no statistically significant difference in volume of intraoperative blood loss between the 2 groups (Z=1.495, P>0.05) and with statistically significant differences in operation time and number of lymph node dissected between the 2 groups (t=2.140, 5.400, P<0.05 ). Lymph node metastasis rate in the SPL group was 8.3%(5/60) in patients with Siewert type Ⅱ AEG and 20.2%(19/94) in patients with Siewert type Ⅲ AEG, with a statistically significant difference (χ²=3.930, P<0.05). Overall incidence of postoperative complications in the SPL group and nonSPL group was respectively 20.13%(31/154) and 13.95%(36/258), with no statistically significant difference between the 2 groups (χ²=2.700, P>0.05). (2) Followup situations: 384 patients were followed up for 48 months (range, 17-89 months). The 3year overall survival rate and diseasefree survival rate were respectively 72.7%, 67.4% in the SPL group and 54.4%, 48.5% in the nonSPL group, with statistically significant differences between the 2 groups (χ²=7.580, 12.380, P<0.05). Stratified analysis showed that 3year overall survival rate and diseasefree survival rate in patients with Siewert type Ⅱ AEG were 72.9%, 63.7% in the SPL group and 65.1%, 59.4% in the nonSPL group, with no statistically significant difference between the 2 groups (χ²=0.280, 0.580, P>0.05). Among patients with Siewert type Ⅲ AEG, 3year overall survival rate and diseasefree survival rate which were 72.4% and 68.3% in the SPL group were significantly higher than that which were 48.3% and 42.2% in the nonSPL group (χ²=8.990, 14.030, P<0.05). (3) Postoperative survival factors analysis in patients with Siewert type Ⅲ AEG and a tumor diameter≥4 cm: results of univariate analysis showed that age, American Society of Anesthesiologists (ASA) score, tumor differentiation, splenic hilar dissection, T stage, N stage and TNM stage were factors affecting postoperative 3year overall survival rate in patients with Siewert type Ⅲ AEG and a tumor diameter≥4 cm (χ²=8.825, 7.485, 6.766, 8.996, 14.024, 26.002, 19.461, P<0.05). There were correlations among age, splenic hilar dissection, N stage, TNM stage and postoperative 3year diseasefree survival rate in patients with Siewert type Ⅲ AEG and a tumor diameter≥ 4 cm (χ²=6.743, 14.038, 26.596, 21.285, P<0.05). Results of multivariate analysis showed that age≥ 65 years, without splenic hilar dissection, T stage and N stage were independent risk factors affecting postoperative 3year overall survival rate in patients with Siewert type Ⅲ AEG and a tumor diameter≥4 cm ［HR=1.817, 0.458, 1.613, 1.312, 95% confidence interval (CI): 1.117-2.955, 0.29²-0.721, 1.129-2.304, 1.004-1.714, P<0.05］. Age≥65 years, without splenic hilar dissection and TNM stage were independent risk factors affecting postoperative 3year diseasefree survival rate in patients with Siewert type Ⅲ AEG and a tumor diameter≥4 cm (HR=1.807, 0.442, 1.799, 95%CI: 1.258-2.596, 0.228-0.679, 1.004-3.224, P<0.05).
Conclusions：LSPL should be performed to patients with Siewert type Ⅲ AEG and a tumor diameter≥ 4 cm due to higher lymph node metastasis rate, and it will be beneficial to survival of patients.