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Table 2. Summary of the meta-analyses comparing RG and LG with respect to short term outcomes
Number Number Time Time
Author Year Country of of Morbidity Blood Operation Retrieved Hospital to oral to first Medical
studies patients loss time LN stay intake flatus cost
Hyun et al. [26] * 2013 Korea 9 7,200 RG = LG RG = LG RG > LG RG = LG RG = LG - - -
Shen et al. [19] 2014 China 8 1,875 RG = LG RG < LG RG > LG RG = LG RG = LG - - -
Chuan et al. [20] 2015 China 5 1,796 RG = LG RG < LG RG > LG RG = LG RG = LG - - -
Hu et al. [21] 2016 China 12 3,580 RG = LG RG < LG RG > LG RG > LG RG < LG - RG > LG -
Wang et al. [23] 2017 China 3 562 RG = LG RG = LG RG > LG RG = LG RG = LG - - -
Chen et al. [22] 2017 China 19 5,953 RG = LG RG < LG RG > LG RG = LG RG = LG RG > LG RG = LG RG > LG
Guerra et al. [25] 2018 Italy 8 2,026 RG = LG** - RG > LG RG > LG RG = LG - - -
*This study included open gastrectomy and compared among robotic, laparoscopic, and open gastrectomy; **only pancreatic
complications were compared, including acute pancreatitis and pancreatic fistula. LN: lymph nodes; RG: robotic gastrectomy; LG:
laparoscopic gastrectomy

to reduce tissue damage and blood loss. Another advantage of RG is a three-dimensional (3D) field of
view that facilitates surgeons to recognize depth perception. Recently, 3D images also became available
in LG; however, special glasses are necessary and the quality of imaging remains inferior to that in RG.
Furthermore, the ergonomics-based surgery console used in RG can reduce the fatigue of operators. While
the surgical devices for RG were limited at first, ultrasonically activated device (harmonic), vessel sealers,
Endo Wrist staplers, and other instruments are now available.

Short-term outcomes
Retrospective studies
Numerous retrospective, case-control studies comparing RG and LG have been conducted, and several
[19]
meta-analyses were performed using those studies [Table 2] [19-26] . Shen et al. conducted 8 studies with
a total of 1,875 patients that showed approximately 40 mL lower blood loss in RG than LG; however, the
operation time for RG was approximately 50 min longer. The duration of hospital stay, morbidity, and
numbers of retrieved lymph nodes were comparable between RG and LG. Other meta-analysis indicated
[25]
similar results, with the exception of a difference between RG over LG with morbidity. Guerra et al.
analyzed 8 studies, including 2026 patients, focusing on pancreatic complications. Pancreatic fistula
occurred in 2.7% of patients receiving RG and 3.8% of patients receiving LG, for an odds ratio of 0.72.
Although the difference was not statistically significant, the authors concluded that RG trended toward
lower rates of postoperative pancreas-related events, despite more unfavorable baseline characteristics
compared with LG.

Prospective studies
Very limited prospective studies of RG have been conducted thus far. We conducted single-center early
and late phase II studies in patients with cStage I gastric cancer to evaluate the safety of RG [27,28] , involving
18 and 120 patients, respectively, in each study that found an incidence of intra-abdominal infectious
complications of Clavien-Dindo classification grade ≥ II of 0% and 3.3%, respectively. Thus, the null
hypotheses were rejected, and the studies concluded that RG can be safely used in cStage I gastric cancer.

In a prospective, multicenter, non-randomized, control study was conducted in Korea from May 2011
to December 2012 to compare the short-term surgical outcomes of RG (n = 223) and LG (n = 211) . No
[29]
significant difference was observed in the incidence of overall postoperative complications (RG 11.9%,
LG 10.3%) and the mortality rate was 0% in both groups; however, the operation time was 40 min longer
and the financial cost was 5,000 USD higher for RG than for LG. The authors concluded that RG was not
superior to LG, and subsequent sub-group analysis showed a significantly lower amount of blood loss in
[30]
RG when D2 lymph node dissection than that in LG .

A multicenter, prospective, single-arm study conducted in Japan evaluated the safety of RG in 330 patients
with cStage I/II gastric cancer enrolled from October 2014 to January 2017, with the primary endpoint of