Hepatocellular carcinoma in patients without cirrhosis : relevance and clinical characteristics

Aim: The present study evaluated the frequency of hepatocellular carcinoma (HCC) in patients without cirrhosis. Methods: HCC patients were recruited from two reference centers for liver disease in Northeast Brazil from 2010 to 2016. The diagnosis of HCC and cirrhosis was based on international criteria. Results: A total of 169 patients were included, and 16% (27) of the patients did not have hepatocellular carcinoma in non-cirrhosis (HCC-NC). The mean age of HCC-NC was 64.4 ± 11.3 years, and 74.1% of the patients were male. The main risk factors were hepatitis C virus (HCV) in 29.6% (8), nonalcoholic steatohepatitis (NASH) in 14.8% (4) and hepatitis B virus (HBV) in 11.1% (3). Histological HCC diagnosis was performed in 81.5% (22) of the patients, and in 18.5% (5) of these patients, the diagnosis was performed by ultrasonography, computed tomography or nuclear magnetic resonance imaging methods. Single nodules were found in 56% of HCC-NC (14) when assessed by imaging methods. Conclusion: The frequency of HCC-NC was elevated and more common in males. HCV, NASH and HBV were the most frequent risk factors. These data contribute to discussion on future protocols and criteria for the early diagnosis and treatment of HCC in patients with chronic liver disease without cirrhosis.


INTRODUCTION
Hepatocellular carcinoma (HCC) is the most frequent primary malignant tumor found in the liver.HCC is also the second cause of deaths related to cancer, accounting for 700,000 deaths every year worldwide [1] .
In Brazil, HCC is the 8th most frequent malignant neoplasm and represents approximately 10,000 cases per year [2] .
A Brazilian national survey conducted in 2009 showed that hepatic cirrhosis was present in 98% of HCC patients, and this tumor was more frequent in cirrhosis patients with hepatitis C virus (HCV), hepatitis B virus (HBV) chronic hepatitis and alcoholic liver disease [3] .However, HCC can also be associated with other liver diseases, such as non-alcoholic fatty liver disease (NAFLD), nonalcoholic steatohepatitis (NASH), and hemochromatosis as well as toxins [4] .
In patients without cirrhosis, the prevalence of HCC varies between 7% to 54% of the cases and can have a major influence on the geographical area [5] .In Western countries, the prevalence of hepatocellular carcinoma in non-cirrhosis (HCC-NC) patients was estimated in 15% to 20% of cases [6][7][8] , and the most common risk factors were HBV and HCV.However, a majority of the information was obtained from Asia and Africa, where the prevalence of hepatitis B and C viral infections is also elevated [9][10][11] .
NASH is considered a relevant risk factor of liver disease worldwide [12] .Associated metabolic syndrome manifestations may also contribute to the development of HCC in patients without cirrhosis [13] .
The present study evaluated the frequency, associated factors and clinical characteristics of HCC in Brazilian patients without cirrhosis.

Design and population study
The present cross-sectional study included patients with HCC diagnosis from two reference centers for liver disease in Northeast Brazil from 2010 to 2016.
Inclusion criteria were as follows: patients diagnosed with hepatocellular carcinoma of different etiologies (NAFLD, HBV, HCV, alcohol, hemochromatosis, and etiology related to toxic agents) Exclusion criteria were as follows: patients diagnosed with hepatocellular carcinoma and cirrhosis.

Diagnostic criteria
The diagnostic criteria for HCC were according to European Association for the Study of the Liver (EASL) recommendations [14] .

Clinical assessment
All the data were obtained from a questionnaire containing the following variables: gender, age, and risk factors for liver diseases (HBV, HCV, NASH, alcohol, and metabolic-and toxic-related factors).The data from physical examinations and completed additional tests [liver, lipid, and glycemic profiles, serum insulin, hepatitis B surface antigen (HBsAg), anti-HCV, ferritin, and transferrin saturation index] were considered.All the patients were also evaluated by at least two imaging methods, such as total abdominal ultrasonography (US), computed tomography (CT) or magnetic resonance imaging (MRI).

Histological assessment
Histological evaluation was performed on liver biopsies or surgical samples.The diagnostic criteria for HCC were based on the recommendations of the International Consensus Panel [15] .

Statistical analysis
The statistical analyses were descriptive and performed with the Statistical Package for the Social Sciences (SPSS) software (version 22.0, IBM Corp., USA).The data were analyzed, and the results are expressed as the mean values, standard deviations, and medians according to the distribution of the variables.The present study was conducted according to the guidelines established in the 1964 declaration of Helsinki.The project was approved by the Research Ethics Committee at Bahia Medicine School, Federal University of Bahia, Brazil.All the participants signed letters of informed consent.

RESULTS
A total of 169 patients with HCC were evaluated, and 16% (27) of the cases were HCC-NC.Table 1 shows the main clinical characteristics and risk factors of the patients without and with cirrhosis.
Histological analysis was performed in 81.5% of the cases (n = 22).A diagnosis was made by imaging methods (CT or MRI) in 18.5% of the cases [Table 2] [16] .

DISCUSSION
The prevalence of HCC-NC in this Brazilian study was elevated (16%), and the results were similar to those found in other studies conducted in Western countries [6][7][8] .The patients were most frequently of advanced ages (mean of 64.4 years) and predominately male.These data are consistent with the findings of previous studies, although in other studies, the diagnosis of HCC-NC was more frequent in younger individuals and in women [5] .This difference may be due to the geographical variations in the prevalence of HCC and its risk factors.
Chronic HBV and HCV infections are the most frequent risk factors for HCC in patients with and without HCC-NC.An estimated 0.1% of individuals with HBV without cirrhosis develop HCC [9] , likely due to the carcinogenic effect of the virus [10] .HCV is described in most studies as being of low potential for developing HCC in the absence of cirrhosis.However, more recent studies have shown the existence of HCC-NC in patients with chronic hepatitis HCV, suggesting that other mechanisms independent of cirrhosis would affect hepatocarcinogenesis [5,11] .However, this scenario could change over the next few years or decades, since effective treatments for the elimination of this virus are currently being used.However, there is a growing increase in NAFLD with the prospect of becoming the leading cause of liver disease worldwide associated with risk factors, such as dyslipidemia, central obesity, diabetes and metabolic syndrome.
In the present study, HCV was also the main risk factor for HCC-NC cases, even in areas of Northeast Brazil, where the prevalence of HCV is low [17] .Perhaps, the prevalence has been influenced by the origin of the patients.The patients in the present study were recruited from reference centers for liver disease.
Chronic HBV infection was also a relevant risk factor for HCC-NC in this patient sample, even after national vaccination programs for this virus.These data are extremely concerning.HBV has a direct oncogenic effect [18] , and patients without cirrhosis are frequently not included in protocols for the early diagnosis of this neoplasm.
NASH, as the second most frequent risk factor after HCV, in the present series of HCC-NC patients, was observed in 14.8% of the cases.Although the prevalence of HCC without cirrhosis in patients with NASH is considered low, in some studies [19][20][21] , NASH also has been recognized as a relevant cause of this liver tumor in patients without cirrhosis.In addition, obesity and diabetes, the major risk factors associated with NAFLD (steatosis and NASH), are also independent risk factors for HCC [13,22] .In the present study, 33% of the HCC-NC patients had diabetes.
In Brazil, a recent national survey that included 110 cases of HCC associated with NAFLD showed that 31% of the cases, diagnosed through liver biopsy, did not present cirrhosis [23] .
In the present study, a single nodule was observed in 68% of the HCC cases.Treatment with curative intent (resection) occurred in 59.3% of the cases.Histopathological evaluation was performed in 81.5% of the cases, and 51.9% of the HCC cases were classified as moderately differentiated tumors.This finding is interesting since the HCC diagnosis was conducted in patients without cirrhosis, who were not included in protocols for early diagnosis and treatment.
Previous studies have also shown that the majority of HCC-NC cases are diagnosed as a single and larger tumor [24,25] , it could be explained because patients with chronic liver disease without cirrhosis are not part of the surveillance protocol, and the diagnosis was performed in patients with more advanced stages.
Although the study presents relevant data, it has some limitations.A lack of knowledge of the prevalence of HCC in the reference population is important because the frequency of HCC-NC may be underestimated.BCLC: Barcelona Clinic Liver Cancer [16] ; CT: computed tomography; MR: magnetic resonance; SD: standard deviation The majority of the clinical information was obtained from patient records, and some of the patients presented incomplete data.
In conclusion, the frequency of HCC-NC in these Brazilian patients was elevated and more commonly observed in men.HCV, NASH, and HBV were the most frequent risk factors associated with HCC-NC.These data contribute to discussions on future protocols and criteria for the early diagnosis and treatment of HCC patients with chronic liver disease without cirrhosis.