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Page 2 of 7 Chouhan et al. Mini-invasive Surg 2018;2:18 I http://dx.doi.org/10.20517/2574-1225.2018.40

laparoscopic rectal resection has shown no increase in overall or disease-free survival , and studies have
[2-4]
suggested caution in the use of laparoscopic surgery in rectal cancer surgery as it is associated with higher
circumferential resection margin (CRM) positive rates, when compared with open surgery . Some inherent
[5]
difficulties with laparoscopic surgery, such as working with rigid straight instruments in a narrow pelvis,
2-dimensional unmagnified views, and poor ergonomics, may have partly affected the oncological outcomes
and increased the rates of positive CRM seen with laparoscopic surgery .
[5]
A robotic platform overcomes some of the limitations of laparoscopic surgery, delivering magnified
3-dimensional views, articulating instruments, offering a stable platform, an extra arm for retraction, and
the ability for the surgeon to sit and operate. A meta-analysis comparing laparoscopic surgery with robotic
surgery in rectal cancer surgery has shown robotic surgery to be safe, and shown better mesolectal dissection
with robotic surgery . Transanal TME (taTME) is a relatively new approach in rectal cancer resection and
[6,7]
the oncological outcome of this approach is yet to be established in rectal cancer surgery. The aim of this
review is to investigate the evidence and show that a robotic platform is the best minimally invasive surgery
(MIS) approach for rectal cancer surgery.

WHY ROBOTIC SURGERY FOR RECTAL CANCER
Technical advantages of robotic surgery
A robotic platform, in comparison with laparoscopic surgery, is more ergonomic, reduces tremors, provides
magnified 3-dimensional views, provides an extra working arm and gives the surgeon control of stable camera
[8]
movements . All these advantages surely help surgeons perform a very precise dissection of the TME plane,
preserving the autonomic nerves . However, due to the loss of haptic feedback with a robotic system, it is
[9]
relatively easy to cause tissue damage during dissection and traction if not careful. A console surgeon can
overcome the tactile feedback limitations of a robotic system by using visual cues, coupled with experience .
[10]
Questionable safety of laparoscopic rectal dissection
Laparoscopic surgery has been shown to have improved short-term outcomes including less postoperative
pain, reduced ileus rate, early discharge and return to work, however the safety of laparoscopic surgery in
rectal cancer surgery is questioned. In a classic trial, laparoscopic surgery was associated with increased
CRM positivity rates compared with open surgery (12.4% vs. 6.3%). Laparoscopic rectal cancer surgery in
particular is associated with a higher conversion rate when compared with colonic laparoscopic resection,
and those that are converted to open surgery have a higher mortality rate [5,11] . This is a possible reflection of
the technical challenges that confront a surgeon during rectal dissection. Recent multicentre randomized
controlled trials (RCTs) have shown that the laparoscopic approach may have a higher potential for inferior
quality TME , however the long-term data on oncological outcomes are still awaited from these trials.
[12]
Potentially better oncological outcomes with robotic rectal surgery
A multicentre study reported excellent short term oncological outcomes with robotic rectal surgery (97%
3-year overall survival) . Non-randomised data out of Korea have shown similar results . The three-year
[14]
[13]
overall survival is 93.1%, with disease-free survival of 79.2%, a low CRM positivity rate of 5.7% and a local
recurrence rate of 3.6%: results which are equivalent to laparoscopic surgery from the same group . Although
[15]
long term data on oncological outcomes with robotic rectal surgery are still lacking, better oncological
outcomes and the low CRM positivity rates seen with robotic rectal surgery are a possible reflection of better
visualisation, and the better ergonomic, stable platform that comes with robotic technology [16,17] .

Kim et al. recently reported a trend towards improved overall survival and cancer-specific survival rates with
[18]
a robotic resection for mid to low rectal cancer (meaning the tumour height from the anal verge was 6.8 cm),
compared with a laparoscopic resection in a retrospective, propensity score matched analysis (224 patients