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Sullivan et al. Hepatoma Res 2018;4:68 I http://dx.doi.org/10.20517/2394-5079.2018.95 Page 3 of 10

livers, there is suggestion of reduced post-operative ascites following laparoscopic resection. Subsequent
large systematic reviews of laparoscopic vs. open hepatectomy for malignant disease further demonstrated
decreased intraoperative blood loss and transfusion requirements, shorter length of hospitalization, and
[6-8]
fewer overall complications . With regards to oncologic outcomes in HCC, compared to open resection,
[9]
laparoscopic resection showed no difference in 1-, 3-, and 5-year OS and DFS . The indications for
[10]
laparoscopic approaches continue to evolve to include both minor and major resections . Based on the
recommendations from the Second International Consensus Conference on laparoscopic liver resection,
‘minor’ hepatectomy (e.g., left lateral sectionectomies, resection of segments 4B, 5, and 6) is increasing
adopted as a standard practice although high-level evidence based on randomized clinical trials (RCTs)
[11]
is still pending . Techniques for minimally invasive “major” resections are still developing, and no
consensus has been adopted, but suffice to say that laparoscopic liver surgery demands a high skill level
with advanced experience in both open resection and laparoscopic proficiency. Overall, many high-
volume centers perform roughly half of their liver resections minimally invasively.

As the robotic platform expands, experience with robot-assisted liver resection (RALR) has increased
dramatically. The robotic approach affords advantages over traditional laparoscopy including optics with
increased magnification and the ability to visualize the surgical field with depth perception. In addition,
the robotic system allows for greater degrees of freedom in the instruments due to the wrist-like action at
joints, facilitating tasks such as suturing for hemorrhage control. For these reasons, it has been suggested
[11]
that the robotic approach is easier to learn as a method of minimally invasive liver surgery . In a review
[12]
by Salloum et al. summarizing the experience of 447 cases of RALR reported in 14 series, the authors
concluded that there is no clear advantage of RALR over conventional laparoscopic hepatectomy at this
time, but more vigorous study designs are necessary to draw meaningful conclusions between different
techniques. Similar to the costs of laparoscopic surgery, increased intraoperative times and equipment
costs of RALR compared to open liver resection are often offset by reduced complications and hospital
length of stay. Our own experience indicates that it is a viable alternative to open liver resection even
[13]
when cost is taken into consideration . Reviews of mostly retrospective data have generally found no
difference in postoperative outcomes including mortality, morbidity, length of hospitalization, and margin
status between laparoscopic and robotic hepatectomy [14-16] . Laparoscopic hepatectomy did demonstrate
[16]
[15]
lower blood loss and reduced operative time as well as cost compared to robotic surgery . Progress
in imaging technology, haptic feedback, vascular control, and artificial intelligence will accelerate the
adoption of the robotic platform, and therefore an additional minimally invasive option versus open
resection, for hepatobiliary surgery in the future. Once considered a large open operation with significant
morbidity, hepatic resection can now be considered a minimally invasive therapy in many instances.

Ablation of hepatic tumors
The ablation of HCC is another option typically utilized in BCLC 0/A-stage tumors that are less than 3 cm
in size. Ablation can be performed using several techniques including thermal, chemical, or non-thermal.
Thermal ablation typically consists of radiofrequency ablation (RFA), which is the application of an
electrical current through the tissue to generate heat and cause coagulation necrosis. RFA has emerged
as the most commonly used ablation technique overall, either via a minimally invasive or open surgical
approach. The long-term results are satisfactory with reported local recurrence rates at 5 years ranging
from 10%-32% and OS has been shown to be 40%-68% at 5 years [17-24] . Several clinical trials have shown
it to be superior to percutaneous ethanol injection [25-28] . Alternatively, microwave ablation (MWA) uses
electromagnetic energy rather than electric current to generate heat, and is less reliant on heat conduction
[29]
compared to RFA. Both methods report similar local control and complication rates . In a RCT of RFA
vs. MWA, the local recurrence rate for RFA was found to be 10% at 2 years compared to 24% for the MWA
[30]
group, although this trend was not found to be statistically significant . But neither RFA nor MWA
should be used when the tumor is adjacent to major vascular or biliary structures, and instead, irreversible