Clinical aspects and treatment of hepatocellular carcinoma in north-eastern Poland

Introduction

Hepatocellular carcinoma (HCC) is the most common (70%) type of primary liver cancer. Recent epidemiological studies conducted in the United States revealed a 4-fold increase in the incidence of HCC over the last 40 years (4.8/100,000 people in 2005-2007), and its incidence is expected to increase to 8.8/100,000 [1]. The highest incidence of HCC was reported from Asia and Africa. The risk of developing HCC in the Polish population, as in most European countries, remains at a low level, and its incidence according to data reported by the World Health Organization (WHO) is 3.2/100,000 people. According to the Polish National Cancer Registry, HCC is diagnosed in approx. 2-2,500 people/year, and the annual mortality for HCC is approx. 2,500 per general population. These statistics indicate unsatisfactory detection and treatment of HCC. Major risk factors for developing HCC include cirrhosis, infection with HBV or HCV, and fatty liver disease. Other risk factors include the toxic effects of alcohol and aflatoxin, adenomas induced by hormonal drugs (contraception, anabolics), and metabolic liver diseases (especially haemochromatosis, associated with a 300-fold increase in risk). HCC is usually diagnosed in cirrhotic patients. It is a heterogeneous tumour characterized by a complex mechanism of development and formation associated with genetic factors regulated by the activation or suppression of cellular oncogenes [2]. The survival of patients with HCC who are not qualified for cancer treatment is usually no longer than several months. The treatment plan for patients with HCC should consider recommendations included in the Barcelona clinic liver cancer (BCLC) staging system, clinical measures of the liver disease (the Child-Pugh score), and the patient’s general well-being (ECOG system). Patients with HCC are treated by partial hepatectomy, ablation, liver transplant and systemic therapy. Nevertheless, combined therapy involving more than one modality is becoming increasingly popular.
The aim of this study was to assess the incidence of cirrhosis, alcohol abuse, hepatitis B virus (HBV) or hepatitis C virus (HCV) infection and fatty liver disease in patients diagnosed with HCC in the population of north-eastern Poland. The usefulness of α-fetoprotein (AFP) in the diagnosis of HCC was analysed in relation to the stage and grade of cancer, and coexisting predictive factors for HCC. The effectiveness of therapies used in the treatment of HCC was assessed.

Material and methods

The severity of liver damage was determined by morphological examination of a liver biopsy specimen, or analysis by means of shear wave elastography (SWE, Aixplorer, Supersonic Imagine, France) or transient elastography (TE, FibroScan Echosense, France). The pathomorphological assessment of cirrhosis and hepatitis relied on the Scheuer classification1 (cirrhosis and hepatitis graded 0 to 4). Cirrhosis in SWE or TE was measured in kilopascals (kPa), and expressed in a 0-4 scoring system, which corresponds to the METAVIR histological scale recommended by the manufacturer and comparable to the Scheuer classification. Infection with HBV was confirmed by detecting the HBs antigen in serum using the micro-enzyme immunoassay (MEIA) and dedicated kits (Abbott, Germany). The concentration of HBV-DNA in serum was analysed by means of RT-PCR and the COBAS AmpliPre/COBAS TagMan HBV Test, version 2.0 (Roche, Germany).
HCV-RNA was quantified using RT-PCR and the COBAS HCV Test, version 2.0 (Roche, Germany). HCV genotypes were identified by electrophoretic amplification. Electropherograms were visualized in the system for documentation and image analysis (UVI-KS400i/Image PC, Syngen Biotech, USA)2.
Alcohol abuse was defined as at least a 2-year-long period of alcohol consumption causing mental and physical addiction.
Serum levels of AFP were measured using a COBAS 6000 apparatus and chemiluminescence tests (Roche, Germany)3.
HCC was treated by thermal ablation using the Cool-tip TM RF Ablation System, E Series (Covidien, Switzerland). Single active electrodes with a 3 cm-long active part and a total length of 10-25 cm were used.
An ultrasonic shear (SonoSurg, Olympus, Japan) was used to dissect the liver parenchyma during partial hepatectomy. Ultrasonically fragmented liver tissue was removed by a suction module, which allowed for the precise dissection of the liver parenchyma and saving vascular structures.
Smaller vessels in the liver parenchyma were sealed using a ThunderBeat electrosurgical generator (Olympus, Japan) or a harmonic knife (Johnson & Johnson, USA).
The study protocol was approved by the Bioethical Committee of the Medical University in Białystok (R-I-002/395/2018).

Statistical analysis

Data were processed using STATISTICA.PL software (StatSoft). The Mann-Whitney U test, Spearman test, Student’s t-test and chi-square test (χ2) were used for statistical analysis. Results were presented as means (x) and their standard errors (SE). The level of significance was adopted at p < 0.05.

Results

Hepatocellular carcinoma was diagnosed in 104 patients from north-eastern Poland over a period of 8 years (2012-2019). Over 90% of patients with HCC were older than 45 years. The incidence of HCC was higher in men than in women. Cirrhosis was diagnosed in 72% of patients. The most common factors associated with the risk of HCC, irrespective of cirrhosis, were infection with HCV and alcohol abuse.
HCC developed in 9/25 (36%) patients positive for HBV despite effective antiviral therapy. Tests of serum samples from these patients were negative for HBV-DNA. HBV viral load was high in the other 16 patients (HBV-DNA ≥ 4 log10 IU/ml).
HCC developed in 3/36 (36%) patients positive for HCV despite effective antiviral therapy. Patients positive for HCV were identified with genotype 1b (n = 30, 83%), genotype 3a (n = 4, 11%), or genotype 4 (n = 2, 6%).
In most cases HCC was located in the right liver lobe, in segments VI, VII and VIII. Initially, 37% of patients were diagnosed with 2-3 focal lesions larger than 5 cm.
Distant metastases from HCC were found in the lungs (n = 6), lymph nodes of the hepatoduodenal ligament (n = 11), and in mediastinal lymph nodes (n = 3). Portal vein tumour thrombosis was diagnosed in 13 patients.
Elevated serum levels of AFP were found most frequently in patients positive for HBV and in patients with portal vein tumour thrombosis. There were no significant differences in the levels of AFP in relation to the size of the tumour, and possible metastases.
Partial hepatectomy and radiofrequency ablation were the most often used methods of HCC treatment in our study.

Discussion

Consistently with other reports, our study revealed significantly higher incidence of HCC in men than women (75% vs. 25%), and in patients aged over 45 years (88%) [1]. Cirrhosis is the most serious risk factor for HCC, which is also consistent with global data. In our study, cirrhosis as an independent risk factor for HCC was diagnosed in 72% of patients. However, 84% of patients with HCC were cirrhotic and positive for HBV, while 69% of patients were positive for HCV (the difference was not significant). Guro et al. and Ding et al. reported even higher incidence of cirrhosis (80-90%) in patients with HCC [3, 4].
Alcoholic cirrhosis was diagnosed in 27% of patients with HCC, but in total 35% of patients with this cancer abused alcohol. Importantly, alcohol consumption is an independent predictor of HCC. Alcohol abuse, smoking and diabetes are increasingly often reported as risk factors for HCC [5].
The association between infection with HBV and HCC is well known. However, the fact that HCC is diagnosed in patients who had effective antiviral therapy is very disturbing. Studies identified the following risk factors for the occurrence of HCC in patients who had successful antiviral treatment: older age, male sex, pre-existing cirrhosis, lower platelet counts, and higher hepatitis B core-related antigens. The annual incidence rate of HCC during nucleotide analogues (NA) treatment was 0.3-1.2% in non-cirrhotic patients and 1.8-6.0% in cirrhotic patients [6]. This may suggest that treatment with nucleoside or NA in some patients does not sufficiently suppress carcinogenesis. A retrospective study by Liu indicated that nucleotide or nucleoside analogue therapy was associated with milder symptoms, fewer and smaller neoplastic lesions on imaging tests, and lower incidence of portal vein tumour thrombosis [7]. Our study also showed that patients successfully treated with antiviral agents and diagnosed with HCC had lower AFP levels, as well as fewer and smaller tumours. However, these observations may be attributed to closer monitoring of patients on antiviral therapy and thus earlier diagnosis of HCC.
The frequency of genotypes in our patients with HCC and positive for HCV was comparable to the frequency of genotypes in the general population of patients infected with HCV. The majority of HCC cases in our study were connected with HCV genotype 1b. The connection between type 1b of the virus and HCC development was confirmed in the literature [8, 9]. However, other researchers suggest an association between HCV genotypes 3 and higher incidence of HCC [10]. So, literature data on this theme are controversial and inconclusive.
Most patients with HCC present with 1 to 3 focal lesions [11], which is also consistent with our observations. In most patients tumours were located in the right liver lobe, in segments VI, VII and VIII. The same tumours’ distribution in the liver parenchyma was observed by authors from China; in 57% of cases HCC was localized in the right lobe [12]. This location is difficult to explain, but it might be associated with the larger volume of the right liver lobe and the hepatic vasculature. Probably, better supply of blood stimulates cell division, which may promote the formation and development of tumour cells in the cirrhotic liver.
Our study found a lower incidence of distant metastases from HCC (15%) compared to data in the literature. However, all researchers have emphasized that metastases from HCC are relatively rare compared to other cancers, which remains an interesting fact [13]. These observations are very important from the clinical and therapeutic point of view.
AFP is a useful marker in the diagnosis of HCC. However, it should never be a decisive test because of the histochemical diversity of primary liver cancers. Some of these tumours do not secrete AFP at all [14]. The analysis of the study population revealed no correlation between the AFP level and the number or total size of hepatic tumours. The highest levels of AFP were measured in patients positive for HBV, patients with diffuse HCC, and those with portal vein tumour thrombosis. In addition, in HBV-positive patients, AFP levels in patients with replicating HBV were significantly higher compared to patients without a detectable viral load. These observations are already used for the assessment of aggressiveness in HCC [15].
Liver transplant is the most effective treatment for HCC. Although the number of patients treated with liver transplant in the study group was small, their survival was the longest. Unfortunately, the growing number of patients with HCC does not make liver transplant possible in all patients who qualify for this procedure. Therefore, alternative treatment methods are being improved.
Currently, partial hepatectomy and tumour resection is a standard therapy in patients with resectable HCC and sufficient liver function. In our study patients with HCC were treated by partial hepatectomy (24%) and thermal ablation (21%). The mean survival time in patients undergoing partial hepatectomy was 19.3 months, and was 3 months longer compared to patients treated with thermal ablation. Meta-analyses of studies on therapies used for HCC and conducted consistently with Cochrane criteria revealed no significant advantage of hepatectomy over thermal ablation, provided that patients were correctly qualified for relevant procedures [16, 17].
Systemic targeted therapy with sorafenib was associated with a mean 5.8 month longer survival compared to patients who received symptomatic treatment. Importantly, sorafenib combined with thermal ablation or partial hepatectomy did not improve the overall treatment success measured by longer survival time [18].
About 29% of patients with HCC in our study were disqualified from surgical treatment due to the advanced stage of cancer or cirrhosis. This rate is very high compared to statistics for other countries in Western Europe, where it was estimated at about 8% [17]. The mean survival time of patients disqualified from treatment was 7.6 months, which is comparable to literature data. Symptomatic treatment in these patients has a significant effect on the quality of life and may extend the patient’s survival to several months [19].

Conclusions

The main predisposing factor for HCC is cirrhosis, followed by alcohol abuse and HCV infection. Effective antiviral therapy for HBV lowers the risk of HCC development, but does not prevent it in all patients. Since 29% of patients were disqualified from HCC treatment due to an advanced stage of cancer, it indicates insufficient screening for HCC. Partial hepatectomy (anatomical and nonanatomical) and radiofrequency ablation (percutaneous and intraoperative) show comparable effectiveness in the treatment of HCC.

Disclosure

The authors declare no conflict of interest.