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conductivity had greatest differences in effect seen in of ablation, which was contrary to previous reports. [29,30]
tumor range. Therefore, some researchers suggested that In the current study, one patient whose tumor was seen
when tumor size > 2 cm, repeated RFA or combination adjacent to the portal vein, hepatic artery, and bile duct
treatment may be beneficial. Second, as reported by by enhanced CT died due to liver failure. Using a pig
[31]
Kim et al., a margin of 3 mm or more is associated model, Lu et al. found that when vessel size was > 3
[20]
with a lower rate of local tumor recurrence after cm, HSE and river-flow effect occurred. Heat could be
percutaneous RFA of HCC. Some clinicians have reported carried away by the blood flow, infusing into regional
difficulty in obtaining adequate circumferential ablative hepatic segments or lobes along the blood flow, causing
margin for large tumors after a single-session of RFA. thermal lesion to liver cells and finally impairing liver
[9]
Overlapping treatment or combining with transcatheter function with sustained high heat. Hence, to achieve
arterial chemoembolization were needed. Third, the “one-off ” ablation and decrease these complications,
[21]
effectiveness of RFA may be related with the perfusion of laparoscopic approaches or pringle maneuver seem to be
the tumor, although it is still debated. Some researchers appropriate for tumors close to vasculature. [31,32]
found that RFA with occlusion of tumor blood supply in
tumors measuring 3.5 cm was beneficial. Documented This study has several limitations. First, most patients did
[22]
pathology showed that blood supplies changed as tumors not have pathological examination. The diagnosis of HCC
grow larger. As the perfusion of tumors aggravated, relied on their hepatitis history and imaging examination.
the “heat-sink effect” (HSE) may be induced which will Therefore, it is possible that benign liver diseases were
influence the effectiveness of the RFA. [23] included, which may influence the judgment of “one-off ”
ablation. Second, all RFA procedures were performed by
In addition to tumor size, proximity of the tumor the same team, which may introduce bias to our results.
to organs is also one of the most important factors Third, our study was a retrospective study, and limited to
influencing the success of “one-off ” ablation. In the clinic, single-center (Eastern Hepatobiliary Surgery Hospital).
tumors adjacent to gallbladder, kidney, diaphragm, and Further analyses including randomized controlled trials
so on were thought to be high-risk. Local ablation for in multi-center sites are needed.
[24]
tumors in “high-risk” location is technically challenging
because of the poor visibility of the tumor and for fear In conclusion, for single HCC with diameters smaller
of collateral thermal injury to the adjacent organs and than 3 cm and which are further from organs, “one-
causing serious post-operative complications. [25,26] The off ” percutaneous RFA was beneficial. Our study also
complication rate of our study is 4.3%, similar to the elucidated the scientific rationale of RFA treatment
report of Lau and Lai, which indicated a complication criteria (AASLD and EASL) for HCC regarding tumor size.
[15]
For tumors located at specific sites of the liver, open or
rate of RFA ranging from 3% to 7%. Most patients laparoscopic RFA or combination with other techniques
experienced mild pain or discomfort during the ablation. may be a better choice.
Six patients had bile leakage on the 3rd or 4th post-
operative day. One patient died from liver failure. These
tumors were all located in “high-risk” areas. To achieve Financial support and sponsorship
This work was supported by the National Natural Science
better ablation effects, some clinicians suggest departing Foundation (No. 81441063) and SMMU Stem Cell and
[27]
the vulnerable structures from the area of ablation or Medicine Research Center’s Innovation Research Program
[28]
using laparoscopic ablation (LA). L A was proved to be (No. 1406).
a safe and effective technique for high-risk lesions not
manageable by percutaneous approach and not suitable Conflicts of interest
for surgical resection. [28]
There are no conflicts of interest.
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[18]
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Hepatoma Research | Volume 2 | Issue 2 | February 29, 2016 51