To compare the short-term clinical efficacies of Da Vinci robotic surgical system-assisted and laparoscopy-assisted radical gastrectomy for locally advanced gastric cancer (GC).

The retrospective cohort study was conducted. The clinicopathological data of 162 patients who underwent minimally invasive radical gastrectomy for locally advanced GC in the First Affiliated Hospital of Army Medical University between September 2016 and September 2017 were collected. Of 162 patients, 65 undergoing Da Vinci robotic surgical system-assisted radical gastrectomy were allocated into the robotic group and 97 undergoing laparoscopy-assisted radical gastrectomy were allocated into the laparoscopic group. According to Japanese gastric cancer treatment guidelines, patients with upper GC and with middle or lower GC underwent respectively total gastrectomy + D₂ lymph node dissection and distal subtotal gastrectomy + D₂ lymph node dissection, and then Billroth Ⅱ or Roux-en-Y digestive tract reconstruction. Observation indicators: (1) surgical and postoperative situations; (2) detection of lymph node; (3) follow-up and survival situations. Measurement data with normal distribution were represented as ±s, and comparisons between groups were analyzed using the t test. Comparisons of count data were done using the chi-square test. Ordinal data were analyzed by the nonparametric test.

(1) Surgical and postoperative situations: all 162 patients underwent successful surgery, without conversion to laparoscopic or open surgery, and pathological resection margins were confirmed as R₀. Volume of intraoperative blood loss, levels of amylase in peritoneal drainage fluid at day 1, 2 and 3 postoperatively, levels of serum amylase fluid at day 1, 2 and 3 postoperatively were respectively (123±39)mL, (557±181)U/L, (357±127)U/L, (183±86)U/L, (181±47)U/L, (123±29)U/L, (85±22)U/L in the robotic group and (142±40)mL, (793±284)U/L, (497±199)U/L, (279±157)U/L, (218±45)U/L, (162±37)U/L, (120±31)U/L in the laparoscopic group, with statistically significant differences between groups (t=-3.015, -2.817, -2.364, -2.132, -2.372, -3.338, -3.720, P<0.05). Cases with distal subtotal gastrectomy + D₂ lymph node dissection and with total gastrectomy + D₂ lymph node dissection, cases with Billroth Ⅱ and Roux-en-Y of digestive tract reconstruction, time of distal subtotal gastrectomy + D₂ lymph node dissection, time of total gastrectomy + D₂ lymph node dissection, cases with anastomotic leakage, pulmonary infection, wound infection or liquefaction and delayed gastric emptying, cases in grading Ⅱ, Ⅲ, Ⅳ and Ⅴof postoperative complications, time of postoperative drainage-tube removal and duration of postoperative hospital stay were respectively 47, 18, 40, 25, (222±37)minutes, (274±43)minutes, 1, 1, 1, 1, 2, 1, 0, 0, (6.5±1.5)days, (10.0±4.0)days in the robotic group and 74, 23, 69, 28, (213±40)minutes, (262±39)minutes, 2, 4, 1, 0, 4, 1, 0, 1, (6.9±1.7)days, (10.0±5.0)days in the laparoscopic group, with no statistically significant difference between groups (χ²=0.326, 1.628, t=1.272, 0.960, χ²=2.501, Z=-1.342, t=-1.142, -0.115, P>0.05). One and 1 patients in the robotic and laparoscopic groups who were complicated with esophagus-jejunum anastomotic leakage after total gastrectomy + Roux-en-Y anastomosis were cured by nutrition support therapy using feeding tube placement under gastroscopy, and 1 patient in the laparoscopic group who were complicated with gastrojejunal anastomosis leakage after distal subtotal gastrectomy + Billroth Ⅱ anastomosis received the second surgical exploration and jejunal feeding tube placement. Patients with pulmonary infection, wound infection or liquefaction and delayed gastric emptying were cured by conservative treatment. Levels of amylase in peritoneal drainage fluid and serum amylase fluid at day 1, 2 and 3 postoperatively were not higher than 3 times of upper limit of normal, without treatment interventions. (2) Detection of lymph node: overall number of lymph nodes detected in the robotic and laparoscopic groups were respectively 36.82±13.41 and 35.21±11.52, with no statistically significant difference between groups (t=0.786, P>0.05). Results of further analysis showed that numbers of lymph node dissected in the 2nd station and upper region of pancreas in patients undergoing distal subtotal gastrectomy + D₂ lymph node dissection were respectively 6.04±3.98, 13.51±6.53 in the robotic group and 4.45±3.12, 11.40±5.30 in the laparoscopic group, with statistically significant differences between groups (t=2.461, 1.986, P<0.05). Numbers of lymph node dissected in No 7 and 8 groups and upper region of pancreas in patients undergoing total gastrectomy + D₂ lymph node dissection were respectively 5.44±2.63, 2.92±1.87, 10.81±4.78 in the robotic group and 3.11±1.82, 1.62±1.33, 7.76±3.34 in the laparoscopic group, with statistically significant differences between groups (t=3.340, 2.689, 2.522, P<0.05). (3) Follow-up and survival situations: of 162 patients, 148 were followed up for 2-14 months, with a median time of 8 months. During the follow-up, patients in the 2 groups had tumor-free survival.

Da Vinci robotic surgical system-assisted radical gastrectomy is safe and feasible. Compared with laparoscopy-assisted radical gastrectomy for locally advanced GC, it has advantages of clear vision of the local anatomy, less intraoperative bleeding, more numbers of lymph nodes dissected in the upper region of pancreas and lighter pancreatic injure, meanwhile, it has also certain operating advantages around the great vessels and in the deep and narrow spaces.

Gastric neoplasms; Advanced stage; Radical resection; D₂ lymph node dissection; Da Vinci robotic surgical system; Laparoscopy; Short-term outcomes