Page 47 - Read Online

Page 4 of 10 Liu et al. Mini-invasive Surg 2020;4:44 I http://dx.doi.org/10.20517/2574-1225.2020.20
[12]
was introduced a year later . Although RAMIE is still under development, it is now described as a
promising minimally invasive operative method with short-term and long-term clinical outcomes that
[29]
are equivalent to (or perhaps better than) those achieved with OE and MIE [Table 2] . In a US report,
[30]
32.1% of esophageal cancer patients were treated with MIE. Of these, 19.6% were RAMIE . In that
report, no differences in postoperative mortality or disease-free survival was noted between MIE and
[30]
RAMIE . Nevertheless, given the many unique advantages of the robot, it is expected to decrease the
morbidity and mortality rates of surgery for esophageal cancer and to improve oncological outcomes.
Results of the recently published ROBOT trial showed improved clinical outcomes with reduced surgical
and cardiopulmonary complication rates, reduced pain and improved functional outcomes with RAMIE
as compared to OE . Moreover, RAMIE was associated with less intraoperative blood loss, lower
[31]
[31]
postoperative pain scores, faster functional recovery, and better quality of life when compared to OE .
Lymph node yield and overall survival did not differ between the two approaches, indicating that RAMIE
offers short-term benefits while maintaining the high oncological standards. Needless to say, evidence
remains weak due to limited RCT results, and more RCT studies are still needed.

[32]
Additionally, Yun et al. showed that RAMIE is also safe and feasible for use with patients who have
received neoadjuvant chemoradiotherapy for locally advanced esophageal cancer, with postoperative
mortality and morbidity rates comparable to that in OE. Another recently published study compared the
clinical benefits of RAMIE with conventional OE. They showed that RAMIE could be a better surgical
option for selected esophageal squamous cell carcinoma patients, offering both short-term and long-term
[33]
benefits . Although both the short-term and long-term outcomes of RAMIE appear equivalent to MIE in
most studies, one paper showed that RAMIE for esophageal cancer patients with node-positive disease in
[34]
the superior mediastinum is associated with increased mortality (7.5%) and morbidity .
LYMPH NODE DISSECTION IN RAMIE
The number of lymph nodes removed is a key factor contributing to the improved survival of esophageal
cancer patients . LND along the recurrent laryngeal nerve (RLN) is considered beneficial; however, RLN
[35]
LND is frequently complicated by RLN palsy (20%-80%), which is especially common on the left side.
Early meta-analysis studies showed that, unfortunately, MIE does not reduce the rates of postoperative
RLN palsy following RLN LND [36-38] . On the other hand, RAMIE has several advantages for LND, especially
RLN LND [Table 2]. The ROBOT trial showed that a mean of 27 and 25 lymph nodes were harvested in
[31]
RAMIE and OE, respectively (not significantly different) , which demonstrated that robotic surgery is at
least comparable to open surgery for retrieving a sufficient number of lymph nodes. Although most early
studies have found that the lymph node yield with RAMIE and MIE are similar [39-41] , in two recent series in
which RAMIE and MIE were applied to upper mediastinal LND, markedly larger numbers of lymph nodes
[44]
were harvested with RAMIE (median 37-49 vs. 19-21) [42,43] . In addition, when Motoyama et al. compared
the number of lymph nodes dissected from around the left RLN, they found that significantly more lymph
nodes were dissected with RAMIE than MIE (median 6 vs. 4). This indicates that a robot-assisted surgical
system may enable more extensive dissection of lymph nodes around the left RLN. Similarly, Park et al.
[42]
demonstrated that the total number of dissected lymph nodes was significantly greater in the RAMIE
group (37.3 ± 17.1 vs. 28.7 ± 11.8; P = 0.003), and intergroup differences were significant for the number
of lymph nodes dissected from both the upper mediastinum (RAMIE: 10.7 ± 9.7 vs. MIE: 6.3 ± 9.3, P =
0.032) and abdomen (RAMIE: 12.2 ± 8.7 vs. MIE: 7.8 ± 7.1, P = 0.007). The five-year overall survival did not
[45]
differ between the two groups (RAMIE: 69% vs. MIE: 59%, P = 0.737). Deng et al. showed that RAMIE
may have an advantage for lymphadenectomy (mean: 20.6 ± 8.8 vs. 17.9 ± 7.7; P = 0.048) over MIE without
increasing the risk of major postoperative complications. A recent propensity-matched analysis of patients
undergoing modified Ivor Lewis esophagectomy also showed that the median total lymph node yield was
27 (range 13-84) in the RAMIE group compared to 23 in the MIE group (range 11-48). With a P-value
of 0.053, their results suggest a trend towards improved lymphadenectomy with RAMIE . These studies
[46]