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Page 2 of 12 Miller et al. Mini-invasive Surg 2021;5:24 https://dx.doi.org/10.20517/2574-1225.2021.25

[3]
described by Menon et al. in 2003, utilization of RARC increased from 0.7% in 2002 to 18.5% in 2012 in
[4]
the United States . Advantages of the robotic approach relative to open radical cystectomy (ORC) include
reduced blood loss, favorable transfusion rate and shorter length of stay .
[5]
Here, we review pertinent oncologic outcomes in the current RARC literature. We queried the PubMed
electronic database in January 2021 for studies that report on oncologic outcomes for RARC. An emphasis
was placed on randomized controlled trials, as well as contemporary comparative open approach cohorts,
large single institution surgical series, multi-center initiatives and systematic reviews. A list of the major
studies considered in this review is found in Table 1.

NODAL YIELD
Lower nodal yield and positive surgical margin status are independently associated with worse OS after
adjustment for neoadjuvant chemotherapy and pathologic factors. In fact, nodal yields of 10-14 have been
proposed as a marker of surgical quality . Professional guidelines and best practice statements are less
[33]
quantitatively prescriptive [1,34] , as patient, clinical and pathologic factors can influence lymph node yield. In a
2015 systematic review, Yuh et al. assessed 105 papers and found that median yield for a robotic approach
[35]
was 19 lymph nodes (range: 3-55) with cumulative analyses finding no difference vs. ORC. Nodal yields are
directly related to the surgical dissection template chosen, whether standard or extended. Among robotic
surgeons, high volume surgeons and institutional volume were independently associated with performance
of extended template dissections .
[36]
[11]
Several RCTs have found comparable nodal yields between RARC and ORC [Table 2]. Nix et al. found
mean LN yields of 19 vs. 18 in RARC vs. ORC (P = 0.51) using a standard dissection template. In the largest
clinical trial, RAZOR investigators found similar median lymph node yields of 23.3 for RARC with 51%
utilizing an extended template, and 25.7 for ORC with 55% utilizing an extended template (P = 0.13) .
[6]
Other smaller RCTs reported similar findings . Several recent meta-analyses did not assess nodal yield [37,38] .
[8,9]

Considering the abundance of data, adequate lymph node yields are achievable via robotic platforms,
including extended and super extended templates. Maintenance of oncologic principles including
performance of a meticulous dissection within pre-defined anatomic boundaries of a template appears to be
more important than surgical approach.

POSITIVE MARGIN RATE
Positive surgical margin (PSM) rate is a measure of local disease burden, an independent predictor of
survival, and can be a measure of surgical quality [33,39,40] . Early criticism of minimally invasive approaches
was that there was risk of higher positive margin rates in locally advanced tumors, as evidenced by a single
non-controlled, non-comparative retrospective study . It was theorized that the lack of tactile feedback
[32]
and learning curve was potential explanations [35,41] .

These early criticisms have largely been refuted. A systematic review showed that PSM rate was low in pT2
disease (< 1.5%) and 0%-25% in pT3 disease or higher, without any significant difference between ORC and
RARC in a cumulative analysis of 17 studies . Interestingly, PSM did not appear to decrease with
[35]
[32]
sequential case numbers or institutional volume , a finding that may reflect surgeons’ willingness to take
on more difficult cases with experience . As a result of these early robotic data and historical open
[35]
cystectomy series, acceptable PSM rates for robotic surgeons were proposed as < 3% for pT2, < 10% for pT3,
< 25% for pT4 and < 7% overall [34,40] .