Study design
This retrospective study has been approved by the Research Ethics Committee of Changhai Hospital, Navy Medical University. The inform consent was exempted in this retrospective study. Demographic baseline and surgical variables of the patients who received DG at Changhai Hospital, Navy Medical University of China during January 2016 and December 2018 were retrospectively collected in this study. All surgeries were performed by four professors with equivalent experiences in the surgical treatment of gastric cancer. The exclusion criteria were: ASA-IV status, Synchronous malignant diseases, combined surgery and missing data for estimation of propensity score (Figure 1).
Through a consensus meeting involving surgeons and biostatisticians, 15 preoperative variables possibly influencing the choice of surgical approach and associated with outcome were identified to enable strict PSM. Each patient’ s propensity score was calculated using a logistic regression model based on age, sex, area,education, body mass index (BMI), operation year, ASA score, operation history, comorbidity, preoperative chemotherapy, preoperatively measured tumor size, clinical T-stage, clinical N-stage, laparoscopic-assisted or open gastrectomy. Patients in iso-URYA and anti-URYA groups were matched 1:1 using the nearest propensity score.
The outcomes included complications, changes in nutritional status, endoscopic findings and gastrointestinal quality of life index (GQLI)[9]. The complication was evaluated by Clavien-Dindo classification [10]. The change in nutritional status was evaluated by the relative values of body weight, hemoglobin, and albumin to the preoperative levels one year after surgery. The endoscopic findings one year after surgery were evaluated by the endoscopic ‘residue, gastritis, bile’ (RGB) classification proposed by Kubo [11], higher scores meant worse signs in the remnant stomach.
Digestive reconstruction procedure
After DG with D2 lymphadenectomy, which was following the Japanese gastric cancer treatment guidelines 2014 (ver. 4) [12], the duodenum was transected about 2 cm distal from the pylorus and the stomach was transected about 4–5 cm proximal to the tumor. A small entry was made at the jejunum on the antimesenteric border 20cm distal to Treitz ligament. Another entry was made at the greater curvature side of posterior wall of gastric stump and 2cm proximal to the stapling line of remnant stomach. The afferent Loop to lesser curvature for anti-URYA or the afferent loop to greater curvature for iso-URYA side-to-side gastrojejunostomy was performed using a 60-mm linear stapler with a blue cartridge. The “Braun enteroenterostomy” was performed by joining the afferent to efferent limb about 10 and 35cm away from gastrointestinal anastomosis, respectively. The afferent intestine was blocked by ligation or stapler at about 3cm away from gastrointestinal anastomosis and several interrupted seromuscular sutures was performed over the blocked site for permanent serosa-to-serosa adhesion (Figure 2). All patients received antecolic gastrojejunostomy and remnant stomach was not fixed to transverse colon mesentery.
Statistical Method
The continuous data were expressed as mean and standard error and the categorical data were expressed as numbers and proportions. Student t-test or Mann-Whitney U test was used to analyze the continuous data and the Pearson χ2 test or the Fisher’s exact test was used to analyze the differences in the categorical data. All the statistical analysis was two tailed test and P values <0.05 was considered to be statistically significant. All statistical analyses were performed using SPSS ver. 22 for Windows (SPSS Inc., Chicago, IL, USA).