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

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.

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 (bstruc200667@gmail.com)

Date received: 20/11/2017 Date accepted: 22/01/2018

* Inclusion criteria: The pathological

finding is HCC, liver tumors (one or two

nodules of 5 cm or smaller in size),

Child-Pugh A or B, prothrombin time more than

50% and platelet count more than

50.000/mm3, unresectable HCC or patients’

refusal to undergo surgery, patients agree

to participate in the study

* Exclusion criteria: Patients with PST

> 2, venous thrombosis (portal vein, hepatic

vein, lower vena cava), bile duct dilation,

distant metastasis or invasion of adjacent

organs

2 Methods

A total of 136 eligible patients were

enrolled in this prospective cohort study

Under the guidance of real-time ultrasound,

the antenna of the microwave system

AveCure (Medwaves, USA) or the electrode

of Valley-lab Cool-tip™ RF Ablation System

(Covidien, USA) was percutaneously probed

into the tumors A RFA was applied for 5 -

12 mins and a MWA for 7.5 - 10 mins until

whole tumor was ablated completely with

a safety margin of 5 - 10 mm Patients

were discharged one day after procedures

A contrast-enhanced CT-scan was

performed 1 month after ablation The

local efficacy was evaluated Complete

ablation was defined as that the ablated

area completely covers the target tumor

Incomplete ablation was defined as any

enhancement within the ablation area or the target tumor [1] All patients with incomplete ablation were further treated

by complementary ablations All patients were regularly followed up every 2 - 3 months during the follow-up

Continuous variables were reported as mean ± standard deviation Differences in categorical variables and continuous variables between the groups were analyzed with the Chi-square test or Fisher’s exact test and with student’s t-test, respectively, using the Stata version 13.0 software The Wilcoxon signed-rank test is used when comparing

evaluated using Kaplan-Meier curve and compared using the log-rank test To identify the prognostic factors for DFS, 12 variables were used, including ablation modality (MWA/RFA), age (< 60, ≥ 60), sex (male, female), albumin (< 3.5; ≥ 3.5 mg%), bilirubine (< 2, ≥ 2 mg%), platelet (< 100, ≥ 100), prothrombin time (< 16,

≥ 16), AFP level (< 200, ≥ 200), tumor differentiation (1, 2, 3), tumor size (< 3,

≥ 3 cm), tumor number (1, 2), BCLC (0, A, B) Variables with p values less than 0.05

in the univariate analysis were entered into a Cox proportional hazards model for multivariate analysis A p-value less than 0.05 was considered statistically significant

RESULTS

1 Patients’ baseline characteristics

Table 1: Characteristics of patients

MWA group (n1 = 66) RFA group (n1 = 70) p

(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 levels after treatment decreased significantly in both two groups

Table 3: Technique effectiveness

MWA group (n2 = 71) p RFA group (n2 = 74)

Nodule size (cm)

Sessions for one

Complete response

(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

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

No significant differences in the complete response rate between modalities (MWA and RFA) and tumor sizes (< 3 cm and ≥ 3 cm)

Table 6: Prognostic factors of DFS

Multivariate analysis

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

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

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

1-year survival (0.76), disease free 2-1-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 progression-free 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]

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),

(< 200, ≥ 200) were the prognostic factors

of DFS after ablations

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