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Figure 1. The da Vinci Surgical System comprises the patient cart, vision cart and surgeon console

[31]
postoperative complication . The incidence of postoperative complications of Clavien-Dindo grade ≥ III
was 2.45%, which was significantly lower than that in the historical control group (6.4%). Based on this
result, RG for gastric cancer has been covered by national health insurance since April 2018 in Japan.

Long-term outcomes
A few retrospective case-control studies have been conducted to compare long-term outcomes between
RG and LG in Japan and Korea [32-34] . In a study conducted in Japan, data from 84 patients who underwent
RG and 437 patients who underwent LG around the same time were retrospectively analyzed; the 3-year
overall survival rates were 86.9% and 88.8%, respectively, and did not differ to a statistically significant
[33]
extent (P = 0.636) . A study conducted in Korea using propensity score matching found 5-year overall
survival rates of 93.2% in RG and 94.2% in LG; again the difference was not statistically significant (P =
[34]
0.4112) . Although not prospective findings, these results indicate that the long-term outcomes of RG are
not inferior to those of LG.

Learning curve
The learning curve for RG is reportedly shorter for experienced surgeons who had performed LG,
estimated to total between 10 and 25 cases [35-39] , although 40-60 cases is the estimated number needed
to reach stabilization in LG [40,41] . Thus, although the 3D imaging and instrument flexibility of RG may
help to make the learning curve less steep, the fact that an expert in LG performed the RG in many cases
could have affected the results. In contrast, a recent study showed that stabilization of the operation
time occurred after 25 cases, even for surgeons without prior LG experience, suggesting that prior LG
[42]
experience is not necessarily required .

Nevertheless, robotic surgery requires surgeons to attain some extent of specialized training. Intuitive
Surgical Inc. provides a training program and surgeons have to pass this program and be certificated as a
Console Surgeon of DVSS to perform RG using DVSS. Interestingly, this training program targets surgeons
from various fields and it is not sufficient to perform RG independently. Therefore, we have developed
three-step educational program targeted at qualified surgeons [Table 3], who should perform more than 10