Comparison of the therapeutic efficacy of microwave ablation and radio-frequency ablation for hepatoccelular carcinomas

Journal of military pharmaco-medicine no2-2018

COMPARISON OF THE THERAPEUTIC EFFICACY OF
MICROWAVE ABLATION AND RADIO-FREQUENCY ABLATION
FOR HEPATOCCELULAR CARCINOMAS
Vo Hoi Trung Truc*; Tran Viet Tu**
SUMMARY
Objectives: Comparison of the therapeutic efficacy of percutaneous microwave ablation (MWA)
and radio frequency ablation (RFA) for treatment of hepatocellular carcinomas (HCC). Subjects
and method: 136 patients with HCC were divided into two groups. 66 patients with 71 tumors
were treated with MWA and 70 with 74 tumors were treated with RFA. Results: The complete
response rate of MWA and RFA were 95.7% and 97.3%, respectively. No significant differences
in the complete response rate between modalities (MWA and RFA) and tumor sizes (< 3 cm
and ≥ 3 cm). The disease-free survival (DFS) rates at 1 and 2 years in the MWA group were
68.2% and 43.9% with a mean DFS period of 17.4 ± 9.2 months. Those at 1 and 2 years in the
RFA group were 65.7% and 41.4%, respectively with a mean DFS period of 16.8 ± 8.7 months.
No significant difference in the DFS rates (p = 0.76 and 0.767) and DFS period (p = 0.446)
between 2 groups. Platelet, age and AFP were identified independent prognostic factors for
DFS by using Cox’s proportional hazards model. Conclusion: MWA has the similar efficacy to
RFA in treating HCCs. Platelet, age and AFP were prognostic factors for DFS.
* Keywords: Hepatocellular carcinoma; Microwave ablation; Radio frequency ablation.

INTRODUCTION
Liver cancer in men is the fifth most
frequently diagnosed cancer worldwide
but the second most frequent cause of
cancer death. In women, it is the seventh
most commonly cancer and the sixth
leading cause of cancer death [3]. Local
ablation therapies have been recognized
as radical, minimally invasive ones for

early HCCs. Among a variety of these,
RFA is the most common thermal ablation
modality worldwide. MWA was first
deployed in Choray Hospital in June 2012
and should be proven its efficacy in
destroying liver tumors in Vietnam.

Therefore, we did this research in order
to: Compare the local ablation effects of
percutaneous MWA and RFA in the
treatment of HCC
SUBJECTS AND METHODS
1. Subjects.
136 patients were diagnosed with
HCCs and treated in the Liver Tumor
Department, Choray Hospital between
June, 2012 and December, 2013. They
were divided into two groups: MWA group
(66 patients with 71 tumors) and RFA
group (70 patients with 74 tumors).

* Choray Hospital
** 103 Military Hospital
Corresponding author: Vo Hoi Trung Truc ()
Date received: 20/11/2017
Date accepted: 22/01/2018

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Journal of military pharmaco-medicine no2-2018
* Inclusion criteria: The pathological

enhancement within the ablation area or

finding is HCC, liver tumors (one or two

the target tumor [1]. All patients with

nodules of 5 cm or smaller in size), Child-

incomplete ablation were further treated

Pugh A or B, prothrombin time more than

by complementary ablations. All patients

50%

were regularly followed up every 2 - 3

and

platelet

count

more

than

3

50.000/mm , unresectable HCC or patients’
refusal to undergo surgery, patients agree
to participate in the study.

months during the follow-up.
Continuous variables were reported as
mean ± standard deviation. Differences in

* Exclusion criteria: Patients with PST

categorical

variables

and

continuous

> 2, venous thrombosis (portal vein, hepatic

variables

vein, lower vena cava), bile duct dilation,

analyzed with the Chi-square test or

distant metastasis or invasion of adjacent

Fisher’s exact test and with student’s

organs.

t-test,

between

respectively,

groups

using

Stata

version

A total of 136 eligible patients were

signed-rank test is used when comparing

enrolled in this prospective cohort study.

two matched samples. DFS curve was

Under the guidance of real-time ultrasound,

evaluated using Kaplan-Meier curve and

the antenna of the microwave system

compared using the log-rank test. To

AveCure (Medwaves, USA) or the electrode

identify the prognostic factors for DFS, 12

of Valley-lab Cool-tip™ RF Ablation System

variables were used, including ablation

(Covidien, USA) was percutaneously probed

modality (MWA/RFA), age (< 60, ≥ 60),

into the tumors. A RFA was applied for 5 -

sex (male, female), albumin (< 3.5; ≥ 3.5

12 mins and a MWA for 7.5 - 10 mins until

mg%), bilirubine (< 2, ≥ 2 mg%), platelet

whole tumor was ablated completely with

(< 100, ≥ 100), prothrombin time (< 16,

a safety margin of 5 - 10 mm. Patients

≥ 16), AFP level (< 200, ≥ 200), tumor

were discharged one day after procedures.

differentiation (1, 2, 3), tumor size (< 3,

A

was

≥ 3 cm), tumor number (1, 2), BCLC (0, A,

performed 1 month after ablation. The

B). Variables with p values less than 0.05

local efficacy was evaluated. Complete

in the univariate analysis were entered

ablation was defined as that the ablated

into a Cox proportional hazards model for

area completely covers the target tumor.

multivariate analysis. A p-value less than

Incomplete ablation was defined as any

0.05 was considered statistically significant.

CT-scan

software.

the

were

2. Methods.

contrast-enhanced

13.0

the

The Wilcoxon

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Journal of military pharmaco-medicine no2-2018
RESULTS
1. Patients’ baseline characteristics.
Table 1: Characteristics of patients.
MWA group (n1 = 66) RFA group (n1 = 70)

p

Sex

Male/female

55/11

62/8

0.379

Age

Mean ± SD

60.8 ± 10.9

62.1 ± 10.7

0.408

Platelet (G/L)

Mean ± SD

154.3 ± 68.5

172.2 ± 68.1

0.129

Fibrinogen (g/L)

Mean ± SD

2.8 ± 1.3

2.8 ± 0.7

0.958

Prothrombin time (sec)

Mean ± SD

13.8 ± 2.2

14.2 ± 1.8

0.312

APTT (sec)

Mean ± SD

31.5 ± 4.3

31.9 ± 5.1

0.615

AST(U/L)

Median (IQR)

61 (46 - 94)

60(45 - 87)

0.459

ALT(U/L)

Median (IQR)

48 (37 - 88)

45(28 - 70)

0.729

Bilirubine (mg/dL)

Median (IQR)

0.9 (0.6 - 1.2)

0.8(0.6 - 1.1)

0.221

Albumin blood (g/dL)

Mean ± SD

4.2 ± 0.6

4.2 ± 0.5

0.629

Tumor differentiation

1/2/3

21/44/1

20/49/1

0.854

A/B

60/6

63/7

1.00

0/A/B

3/59/4

5/63/2

0.579

PST

0/1

62/4

66/4

1.00

The number of nodules

1/2

61/5

66/4

0.739

Median follow-up time

Median (IQR)

24.7 (14 - 25.7)

24.4 (15.7 - 25.4)

0.806

Child-Pugh
BCLC

(n1: Total number of patients)
There was no significant difference in clinical backgrounds between the two groups.
2. Ablation effectiveness.
Table 2: AFP changing after treatments.
AFP level

MWA group (n1 = 66)

RFA group (n1 = 70)

Before the procedure

Median (IQR)

11.8 (6.0 - 39.7)

11.2 (5.8 - 28.9)

After the procedure

Median (IQR)

7.5 (4.6 - 19.4)

8,1 (3.6 - 13.3)

< 0.001

< 0.001

p

AFP levels after treatment decreased significantly in both two groups.
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Journal of military pharmaco-medicine no2-2018
Table 3: Technique effectiveness.
MWA group (n2 = 71)

p

RFA group (n2 = 74)

< 2/2 - 3/>3

3/27/41

0.534

5/33/36

Mean ± SD

3.3 ± 1

0.573

3.2 ± 1

1/≥ 2

57/14

0.504

56/18

Mean ± SD

1.2 ± 0,4

0.220

1.3 ± 0.6

Nodule size (cm)

Sessions for one

nodule

Complete response

Overall

95.8%

97.3%

Nodule ≤ 3 cm

97%

97.5%

Nodule > 3 cm

94.6%

97.1%

(n2: Total number of nodules)
No significant differences in nodule sizes and the number of ablation sessions for
the target nodule were observed between the MWA and the RFA groups.
The CA rate in the tumor treated with MWA was the same as one in the tumors
treated with RFA.
3. Disease free survival.
Table 4: DFS and rate.
MWA group (n1 = 66)

RFA group (n1 = 70)

p

Disease free 1-year survival

68.2%

65.7%

0.76

Disease free 2-year survival

43.9%

41.4%

0.767

17.4 ± 9.2 (months)

16,8 ± 8.7 (months)

0.724

Mean DFS

No significant differences in the DFS rates and DFS period between two groups.

4. Prognostic factors.
Table 5: Prognostic factors of complete response.
Multiple linear regression
Odds ratio

p-value

95%CI

Ablation modality (MWA/RFA)

1.5

0.64

0.2

9.6

Nodule size (≤ 3 cm, > 3 cm)

0.6

0.64

0.1

4

No significant differences in the complete response rate between modalities (MWA

and RFA) and tumor sizes (< 3 cm and ≥ 3 cm).
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Journal of military pharmaco-medicine no2-2018
Table 6: Prognostic factors of DFS.
Multivariate analysis
Hazard ratio

p-value

95%CI

Age(< 60, ≥ 60)

0,6

0.021

0,4

0,9

Platelet (< 100, ≥ 100)

0.4

0.002

0.2

0.7

AFP level (< 200, ≥ 200)

1.5

0.013

1.1

1.9

Variables were analyzed: ablation modality (MWA/RFA), sex (male, female), age
(< 60, ≥ 60), albumin (≤ 3.5; > 3.5 mg%), bilirubine (≤ 2, > 2 cm), platelet (< 100,
≥ 100), prothrombin time (< 16, ≥ 16), AFP level (< 200, ≥ 200), tumor differentiation
(1, 2, 3), nodule size (< 3, ≥ 3 cm), nodule number (1, 2), BCLC (0, A, B)
Age, platelet count and AFP were independent prognostic factors of DFS.
DISCUSSION
There was no significant difference in
clinical backgrounds between the two
groups. AFP levels after treatment decreased
significantly in both two groups.
1. Technique effectiveness of MWA.
Complete response confirmed at 1 month
after treatment is very important. It is one
of the main criteria to evaluate the efficacy
of ablation. The complete response rate
of MWA group was 95.8%. This rate is not
different from many other studies. Liu et al

realized that 85.7% of tumors in the
915 MHz MW group and 73.7% of tumors
in the 2,450 MHz MW group achieved
complete ablation [4]. Xu et al found that
the complete response was 94.6%.
In our study, there was no difference
between the complete response rate in
nodules ≤ 3 cm and the one in nodules
> 3 cm (p = 0.64) [7]. Hetta et al showed
that MW ablation success was higher with
nodules ≤ 3 cm (98.3%) in comparison to
nodules > 3 cm (92.5%). However, the
138

difference was not significant (p = 0.301)
[2]. Lu et al documented the complete
response rate achieved using MWA group
was 94.9%. Complete response rates were
98.6% in tumors ≤ 3 cm versus 83.3% in
tumors > 3 cm (p = 0.01) [8]. Wang et al
found that patients with tumor > 5 cm
were less likely to gain complete ablation
at first microwave ablation and more
likely to suffer from incomplete ablation
after two sessions of MWA compared with
those with tumor ≤ 5 cm. However, tumor
number and location have no significant
impact on technique effectiveness [6].
2. The therapeutic efficacy of MWA
versus RFA.

Theoretically, MWA outperforms RFA
in some areas, such as faster ablation
time, bigger coagulation volume, higher
tumor temperature and being less affected
by the heat-sink effect of local blood vessels.
However, we found that the CR rates using
MWA and RFA were 95.8% and 97.3%,
respectively. There was no difference


Journal of military pharmaco-medicine no2-2018
between the two groups (p = 0.64). Lu et
al found that the complete response rates
were 94.9% using MWA versus 93.1%
using RFA (p = 0.75) [8]. Zhang et al
reported the complete response rate was
achieved in 86.7% of tumors treated with
MWA and 83.4% of the treated those with
RFA, with no significant difference between
the two groups (p = 0.957) [9]. Xu et al
found that the complete response rate in
MW and RF ablation was 94.6% and
89.7%, respectively (p > 0.05) [7].
3. Disease free survival.
According to our study, the 1-year and
2-year DFS rates in the MWA group were
68.2% and 43.9%, respectively with a
mean DFS period of 17.4 ± 9.2 months.
The 1-year and 2-year DFS rates in the
RFA group were 65.7% and 41.4% with a

mean DFS period of 16.8 ± 8.7 months.
There was no difference in disease free 1year survival (0.76), disease free 2-year
survival (p = 0.767) and mean DFS period
(p = 0.724) between the two groups. The
outcome in our study is better than that in
the Lu et al’s study. Lu et al showed that
the DFS rates at 1, 2, 3 years in the
MWA group were 45.9%, 26.9%, 26.9%,

respectively, with a mean DFS period of
15.5 months. The DFS rates at 1, 2, 3
years in the RFA group were 37.2%,
20.7%, 15.5%, respectively, with a mean
DFS period of 16.5 months (p = 0.53) in
comparison with the MWA group [8].
Zhang et al showed that the 1-, 3-, 5-year
DFS rates were 62.3%, 33.8%, 20.8%,
respectively, for the MWA group and
70.5%, 42.3%, 34.2%, respectively for the
RF ablation group. There was no significant
difference between these two groups
(p = 0.123) [9]. Vogl et al reported that the
progression-free survival rate at 1 and
2 years were much higher than ours. In
the Vogl et al’s study, the progressionfree survival rate for patients treated with
MWA of 1, 2, 3 years were 97.2%, 94.5%,
91.7 and treated with RFA were 96.9%,
93.8%, and 90.6%, respectively (p = 0.98)
[5]. The difference was not significant
between the two groups (p = 0.98) [5]. We

confirmed that the prognostic factors of
DFS were age (< 60, ≥ 60), platelet
(< 100, ≥ 100) and AFP level (< 200,
≥ 200). Wang et al identified levels of AFP
and GGT as independent prognostic
factors of recurrence-free survival in
patients receiving MWA [6].

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Journal of military pharmaco-medicine no2-2018

CONCLUSION
Findings in this study revealed that the
complete response rates of MWA and
RFA were 95.8% and 97.9%, respectively.
There was no difference between the two
groups (p = 0.64). There was no difference
between the complete response rate in
nodules ≤ 3 cm and the one in nodules
> 3 cm (p = 0.64). The 1-year and 2-year
DFS rates in the MWA group were 68.2%
and 43.9% with a mean DFS period of
17.4 ± 9.2 months. The 1-year and 2-year
DFS rates in the RFA group were 65.7%
and 41.4% with a mean DFS period of
16.8 ± 8.7 months. There was no difference
in disease free 1-year survival (0.76),
disease free 2-year survival (p = 0.767).

We confirmed that age (< 60, ≥ 60),
platelet (< 100, ≥ 100) and AFP level
(< 200, ≥ 200) were the prognostic factors
of DFS after ablations.
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