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ORIGINAL ARTICLE
Year : 2017  |  Volume : 30  |  Issue : 4  |  Page : 1220-1225

Study of γ-glutamyltranspeptidase as a prognostic marker in radiofrequency: Ablation treatment of hepatocellular carcinoma


1 Department of Tropical Medicine, Faculty of medicine, Menoufia University, Menoufia, Egypt
2 Department of Medical Biochemistry, Faculty of medicine, Menoufia University, Menoufia, Egypt

Date of Submission17-Dec-2015
Date of Acceptance11-Mar-2016
Date of Web Publication04-Apr-2018

Correspondence Address:
Basma Mohiy Eissa
Shebin El Kom, Menoufia
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/mmj.mmj_515_15

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  Abstract 


Objective
This study was conducted to investigate the prognostic significance of γ-glutamyltranspeptidase (GGT) serum levels in patients undergoing radiofrequency ablation (RFA) therapy for the treatment of hepatocellular carcinoma (HCC).
Background
HCC is one of the prominent types of malignancies and ranks third in mortality worldwide. RFA is regarded as an alternative to surgical resection for curative treatment of a small HCC. GGT is a key enzyme that catalyzes the transpeptidation and hydrolysis of the C-terminal glutamyl group of glutathione and related molecules, and it correlates with biotransformation, nucleic acid metabolism, and tumorigenesis.
Patients and methods
This study was conducted on 20 patients with a small HCC who had been treated with RFA. Baseline serum GGT was estimated before therapy and then after 1–2 months to see its possible prognostic tool as a marker in HCC. In addition, 20 apparently healthy individuals matched for age and sex were selected as a control group.
Results
Our study revealed that level of GGT was significantly reduced compared with pretreated level in patients with HCC treated with RFA. Moreover, high GGT level and big tumor size were risk factors for recurrence.
Conclusion
We can use GGT as a marker for prognosis of HCC patients treated with RFA.

Keywords: γ-glutamyltranspeptidase, hepatocellular carcinoma, radiofrequency ablation


How to cite this article:
Nouh MA, Abd Elgayed EM, Eissa BM. Study of γ-glutamyltranspeptidase as a prognostic marker in radiofrequency: Ablation treatment of hepatocellular carcinoma. Menoufia Med J 2017;30:1220-5

How to cite this URL:
Nouh MA, Abd Elgayed EM, Eissa BM. Study of γ-glutamyltranspeptidase as a prognostic marker in radiofrequency: Ablation treatment of hepatocellular carcinoma. Menoufia Med J [serial online] 2017 [cited 2020 Feb 27];30:1220-5. Available from: http://www.mmj.eg.net/text.asp?2017/30/4/1220/229227




  Introduction Top


Hepatocellular carcinoma (HCC) is one of the predominant types of malignancy and ranks third in mortality worldwide[1]. According to the WHO, the burden of HCC is expected to continue to increase until 2030, and the incidence and mortality rates for HCC are virtually identical, reflecting the overall poor survival of patients with this tumor[2]. HCC generally develops in cirrhotic livers. The various underlying chronic liver diseases that result in cirrhosis have a variable incidence of HCC development. Viral hepatitis B and C (HBV, HCV) are among the most frequent causes of HCC worldwide[3]. Radiofrequency ablation (RFA) is regarded as an alternative to surgical resection for curative treatment of small HCC, and its efficacy in terms of long-term survival is comparable to that of resection[4]. Because of minimal invasiveness of RFA and little damage to the liver it may be used in the treatment of small HCCs in patients with cirrhosis; such patients are not able to tolerate surgical resection. Therapy using RFA may also be used as a bridging treatment before liver transplantation, as the prolonged waiting time for cadaveric livers may lead to dropouts from the waiting list[5]. γ-Glutamyltranspeptidase (GGT) is a key enzyme that catalyzes the transpeptidation and hydrolysis of the C-terminal glutamyle group of glutathione and related molecules, and it correlates with biotransformation, nucleic acid metabolism, and tumorigenesis[6]. Serum GGT level has also been characterized as a biomarker for oxidative stress and shown to correlate with inflammation in the extracellular tissue microenvironment[7].

Over the last few years, several studies have focused on possible relationship between GGT and incidence of HCC development, recurrence, and poor prognosis[8].

On the basis of increasing evidence of the importance of GGT in carcinogenesis and inflammation, we decided to explore the prognostic significance of the enzyme level in HCC patients treated with RFA.


  Patients and Methods Top


The protocol was approved by the ethical committee of Menoufia university and an informed written consent was obtained from each participant. The present prospective study was conducted on 20 patients and 20 healthy individuals of matched age and sex as controls. These patients with HCC who had been treated with RFA at Fever Hospital of Shieben El Kom between October 2014 and March 2015 were diagnosed with tumors showing intense arterial uptake of contrast agent, followed by wash out in the venous delayed phases, using contrast-enhanced MRI or computed tomography (CT)[9]. Tumor biopsy was used to diagnose tumor with nonclassical imaging findings.

There were 14 male and six female patients. Their ages ranged between 38 and 75 years. Informed consent was obtained before patients entered the study.

Inclusion criteria for patients with HCC were as follows: (a) no previous treatment for HCC; (b) liver function of Child–Pugh class A or B; (c) a single lesion of less than or equal to 5 cm in diameter, or less than three lesions with the largest tumor diameter of less than or equal to 3 cm; and (d) no invasion of major intrahepatic vessels or extrahepatic metastasis.

According to clinical manifestation, criteria for exclusion were any patients with previous treatment for HCC, decompensated liver (i.e., ascites and hematemesis), multiple lesions more than three or large lesions more than 5 cm, or metastasis.

All patients and controls were subjected to the following: complete history taking, full clinical examination, routine laboratory investigations including complete blood picture, erythrocyte sedimentation rate[10], liver function tests, including alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase, serum bilirubin (direct and indirect), serum proteins, serum albumin[11], prothrombin time, and international normalized ratio[11], renal function tests, including serum urea and creatinine, and hepatitis markers, hepatitis B surface antigen[12]and anti-HCV antibody[13]. Measurement of serum α-fetoprotein (AFP) and GGT as tumor markers was carried out using enzyme-linked immunosorbent assay technique.

Imaging studies

Abdominal and pelvic ultrasonography was performed for patient groups and also triphasic abdominal and pelvic CT scanning was performed before and after treatment.

Sample collection

A volume of 5 ml of blood sample was drawn into plain tube from each patient 1 or 2 days before RFA was performed. Blood samples were centrifuged and serum stored at –20°C until analyzed.

Follow-up observation after radiofrequency ablation treatment

Patients were followed up with an interval of 2 months. AFP and GGT serum levels were estimated, and liver function test, ultrasound, and CT were performed.

Statistical analysis

Results were collected, tabulated, and statistically analyzed using statistical package SPSS version 20 (SPSS Inc., Chicago, Illinois, USA).


  Results Top


This study was conducted on 20 patients and 20 healthy individuals of matched age and sex as controls. Patients with HCC were treated using RFA at Fever Hospital of Shieben El Kom between October 2014 and March 2015.

Statistical analysis of the results of the present study revealed that there was no significant difference between patients and controls as regards sex, and age ranged from 38 to 75 years with a mean age of 55.25 ± 8.27 years. As regards sex distribution, the present study showed that HCC is more prevalent in men than in women, being 3.8 times higher in men than in women.

In the present study, chronic HCV was the most common etiology of cirrhosis in the HCC group, representing 100% of cases; HBV was less frequent (0.5%).

There was a nonsignificant difference between patient groups as regards international normalized ratio and total bilirubin, and there was a highly significant difference as regards albumin, ALT, and AST [Table 1] and [Figure 1].
Table 1: Statistical comparison between hepatocellular carcinoma patients and normal controls as regards liver function tests

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Figure 1: Comparison between studied groups as regards alanine transaminase and aspartate transaminase.

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There was a nonsignificant difference between pretreated groups as regards hemoglobin and total lymphocyte count and it showed a highly significant difference as regards platelet count.

This study showed a significant reduction between studied groups as regards AFP with a mean ± SD of 159.99 ± 277.87 before treatment and 97.09 ± 159.73 after treatment [Table 2] and [Figure 2].
Table 2: Distribution of the studied patients as regards α-fetoprotein and γ-glutamyltranspeptidase before and after treatment

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Figure 2: Comparison between studied patients as regards a-fetoprotein before and after treatment.

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This study showed a significant reduction between studied groups as regards GGT before and after treatment of HCC with RFA with a mean ± SD of 176.70 ± 76.18 before treatment and 124.80 ± 60.78 after treatment [Table 2] and [Figure 3].
Figure 3: Comparison between studied patients as regards γ-glutamyltranspeptidase before and after treatment.

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As regards tumor size and completeness of ablation, in this study we found that tumor size and baseline GGT were independent factors related to recurrence after RFA for HCC, as in this study 15% of patients had recurrence. The results suggested that high GGT level was related to large tumor [Table 3] and [Figure 4].
Table 3: Serum α-fetoprotein and γ-glutamyltranspeptidase levels in distribution according to tumor size in the studied hepatocellular carcinoma patients

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Figure 4: Serum γ-glutamyltranspeptidase levels in relation to tumor size in the studied hepatocellular carcinoma patients.

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In the current study the area under receiver operating characteristic curve (AUROC) for GGT was 0.94, and at a cutoff point greater than or equal to 49 IU/l the sensitivity of GGT was 90% and specificity was 75%.

With combined use of AFP and GGT the sensitivity increased to 100%, specificity was 35%, accuracy was 68%, positive predictive value was 61%, and negative predictive value was 100% [Table 4],[Table 5],[Table 6].
Table 4: Validity of α-fetoprotein

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Table 5: Validity of γ-glutamyltranspeptidase

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Table 6: Validity of combined γ-glutamyltranspeptidase + α-fetoprotein

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There was a significant increase in sensitivity, accuracy, and negative predictive value with combined use of AFP and GGT compared with FP alone in the diagnosis of HCC.


  Discussion Top


GGT is a key enzyme that catalyzes the transpeptidation and hydrolysis of the C-terminal glutamyl group of glutathione and related molecules, and it correlates with biotransformation, nucleic acid metabolism, and tumorigenesis[6]. Serum GGT level has also been characterized as a biomarker for oxidative stress, and shown to correlate with inflammation in the extracellular tissue microenvironment. Over the last few years, several studies were focused on the possible relationship between GGT and the incidence of HCC development, recurrence, and poor prognosis[7].

On the basis of increasing evidence of the importance of GGT in carcinogenesis and inflammation, we tried to explore the prognostic significance of the enzyme level in HCC patients treated using RFA. We measured AFP and GGT 1–2 days before RFA and 2 months after. This study was conducted on 20 patients with HCC who are treated using RFA and 20 healthy individuals as controls. As regards age distribution in the HCC group, the present study showed that age ranged between 38 and 75 years with a mean age of the patients of 55.25 ± 8.27. This is in agreement with Amer et al.[14], who reported that the mean age of the patients with HCC was 54 ± 8.6 years, whereas Yang and Roberts[15]found HCC to be more frequent in individuals of an average age of 64 years and El-Serag[16]reported that HCC is rare before 40 and peaks around the age of 70 years. The endemicity of HCV infection in Egypt, in addition to other contributing environmental factors such as the presence of aflatoxin in many food stuff and contamination with insecticides, may explain the occurrence of HCC at younger age groups[17].

As regards the sex distribution the present study showed that HCC is more prevalent in men than in women, being 3.8 times higher in men than in women; these results are in agreement with El-Serag[16], who reported that there was a striking male HCC predominance, with the highest male: female ratios (averaging between 2:1 and 4:1) in high HCC incidence areas. Bosch et al.[18] also found that men were at higher risk for HCC compared with women, and the incidence ratio varied in different parts of the world, being 1.3–3.6 times higher in men. Male sex predominance of HCC may be attributed to sex hormones and sex-specific differences in exposure to risk factors. Men are more likely to be infected with HBV and HCV, consume alcohol, smoke cigarettes, and have increased iron stores. However, experiments show a two to eight-fold increase in HCC development in male mice. These data support the hypothesis that androgens influence HCC progression rather than sex-specific exposure to risk factors[16].

In the present study chronic HCV was the most common etiology of cirrhosis in the HCC group, representing 100% of cases; HBV was less frequent (0.5%). This is in agreement with Amer et al.[14], who found that the major risk factor for cirrhosis and the subsequent development of HCC was chronic hepatitis C (67.7%) and to a lesser extent chronic hepatitis B (8.8%).

This study showed a highly significant increase as regards ALT and AST and a significant reduction as regards albumin and platelets. This is in agreement with Fernandez et al.[19], who reported that the levels of angiogenesis factors were found to positively correlate to serum transaminase, suggesting the role of these factors in the pathogenesis of fibrosis stage and inflammatory activity.

Kawamura et al.[20] reported that thrombocytopenia, a marker for cirrhosis, is associated with subsequent HCC development.

As regards tumor size and completeness of ablation, in our study we found that tumor size and baseline GGT were independent factors related to recurrence after RFA for HCC. Results suggested that high GGT level was related to large tumor size; this is in agreement with Xia et al.[21], who found that tumor size and completeness of ablation are two most important prognostic factors for recurrence after RFA for HCC.

This study showed a significant reduction between studied groups as regards AFP with a mean ± SD of 159.99 ± 277.87 before treatment and 97.09 ± 159.73 after treatment.

The value of AFP in the diagnosis of HCC was variable in different studies. Chan et al.[22]found elevated serum AFP levels not more than 200 ng/ml in patients with benign liver conditions such as hepatitis and cirrhosis. Moreover, Yoshida et al.[23]reported normal AFP levels in approximately one-third of patients with HCC; a large number of HCC patients have AF P values less than 400 ng/ml, making them very difficult to undergo detection and prognosis of HCC.

Similarly, Tsai et al.[24]observed that an AFP level less than 400 ng/ml was noted in 51% of HCC patients. Furthermore, at least one-third of small HCC and up to 30% of advanced HCC will be missed unless other diagnostic tools are used. In addition, AFP may be elevated in nonmalignant liver diseases, and hence it is obvious that AFP alone is not a reliable indicator for the detection and prognosis of HCC.

As regards GGT before and after treatment of HCC with RFA, the mean ± SD was 176.70 ± 76.18 before treatment and 124.80 ± 60.78 after treatment. This is in agreement with Corti et al.[7], who reported that GGT, as a key enzyme involved in glutathione metabolism, can exert pro-oxidative effects at the membrane surface and in the extracellular microenvironment. This phenomenon may be explained by the high reactivity of cysteinyl–glycine, the product of glutathione hydrolysis by GGT. The pro-oxidative activity of GGT may contribute to persistant oxidative stress that has been described in cancer, to modulation of processes involved in tumor progression, such as cell proliferation or apoptosis, and to protective adaptation against electrophilic or alkylating compounds.

Zhou et al.[25]reported that GGT value is too weak to be used as the only marker for HCC; it has been described as working more effectively when combined with AFP.

In the current study the AUROC for AFP was 0.82, and at a cutoff point greater than or equal to 6.05 ng/ml the sensitivity of AFP was 85% and specificity was 60%. Trevisani et al.[26]reported that in HCC specificity varies from about 76 to 96% and increases with elevated cutoff value. Omran et al.[27]reported that AFP showed an AUROC of 0.611 with a sensitivity of 63% and specificity of 43% at a cutoff level of 16.5 ng/ml. Moreover, El-Shafie et al.[28]found that AFP had a sensitivity of 77.4% and a specificity of 60% at a cutoff of 28.51 ng/ml.

In the current study the AUROC for GGT was 0.94, and at a cutoff point greater than or equal to 49 IU/l the sensitivity of GGT was 90% and specificity was 75%.

Cui et al.[29] reported that sensitivities of GGT have been reported to be 74.0% in detecting HCC. Furthermore, the simultaneous determination of GGT and AFP can significantly improve sensitivity over AFP alone.

With combined use of AFP and GGT the sensitivity increased to 100%, specificity was 35%, accuracy was 68%, positive predictive value was 61%, and negative predictive value was 100%.

There was a significant increase in sensitivity, accuracy, and negative predictive value with combined use of AFP and GGT compared with AFP alone in the diagnosis of HCC.

Therefore, GGT may be a valuable tumor marker in detecting small HCC and good supplementary to AFP in the diagnosis of HCC and follow-up patients after RFA therapy. The present study had certain limitations, including small number of patients. Therefore, further studies investigating larger patient populations are required to validate the results of the study.


  Conclusion Top


From the present study we concluded that serum GGT increases in patients with HCC than in controls. Combined GGT and AFP increases sensitivity and negative predictive value for the diagnosis and prognosis of HCC patients treated with RFA.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]



 

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