Prognosis Factors of Young Patients Undergoing Curative Resection for Hepatitis B Virus-Related Hepatocellular Carcinoma: A Multicenter Study

Introduction

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide.¹ Patients with hepatitis B virus (HBV) infection are one of the major risk factors for the development of HCC, particularly those with chronic liver disease and cirrhosis.² It is associated with 70–90% of patients with HCC in the highly endemic Asia-Pacific region, particularly in China.³ There are various kinds of treatments for HBV-related HCC, such as liver resection, liver transplantation, transarterial chemoembolization, radiofrequency ablation, etc.⁴ Liver resection is a mainstay of treatment for HBV-related HCC patients.⁵

With the development of modern medical technology and screening programs, HBV-related HCC is detected to be getting younger.^2,6,7 However, a limited number of studies have reported the prognosis of young HBV-related HCC patients and the conclusions are variable. Some authors have found that young patients have better long-term outcomes,^8–10 whereas others have reported that young patients have advanced tumor factors, thereby indicating a poor prognosis.^11,12 Several studies have demonstrated that the long-term outcomes after HCC resection are similar between young and older groups.^13–15 Most of these studies enrolled less than 100 patients investigated the prognosis of young HCC patients. Hence, it remains controversial whether the prognosis of HCC in young patients is different from that in older patients.

To address this issue, we conducted a large multicenter study to compare the clinicopathological features and the prognosis of young patients (age ≤40 years) versus older patients (aged >40 years) with HBV-related HCC after curative resection.

Methods

Patients and Study Design

This study was approved by the institutional ethics committee of Mengchao Hepatobiliary Hospital of Fujian Medical University (NO.:2019_069_01). Informed consent was obtained from each patient for their data to be used for research purposes. HBV-related HCC patients who underwent liver resection between January 2008 and December 2015 were extracted from primary liver cancer big data by an IT engineer, and then were verified by two researchers (Dr. Jianxing Zeng and Dr. Kongying Lin) in this study.

The inclusion criteria included: (1) 0 to 1 score of performance status,¹⁶ (2) positive hepatitis B surface antigen (HBsAg) and negative hepatitis C antibody, (3) no evidence of extrahepatic metastasis, (4) no history of preoperative anticancer treatment, (5) no history of other malignancies, and (6) curative resection with tumor-negative resection margins (R0 resection).¹⁷ Patients who received palliative tumor resection, received recurrent tumor resection, had incomplete clinical data, died of severe surgical complications, and lost to follow-up within 60 days after discharge were excluded.

All patients received routine serological examination including white blood cell, platelet count, total bilirubin, albumin, alpha-fetoprotein (AFP), hepatitis B virus and hepatitis C virus immunology, and HBV deoxyribonucleic acid (HBV-DNA) load. Imaging studies included chest radiography, abdominal ultrasonography, and contrast-enhanced computed tomography (CT)/magnetic resonance imaging (MRI) of the abdomen.

Histopathological study of the resected specimens was performed independently by three pathologists who came to a consensus by discussion if there was any controversy. Histologic grading of HCC was based on the Edmondson-Steiner classification.¹⁸ The criterion of the American Association for the Study of Liver Diseases was used for pre-operative clinical diagnosis of HCC.¹⁹ All patients were staged using the American Joint Committee on Cancer (AJCC) staging system and Barcelona Clinic Liver Cancer (BCLC) staging system.^20,21

Follow-Up

Patients were followed up once every 3 months for the first 2 years after discharge from hospitals and every 3–6 months in subsequent years. The follow-up program included liver function, AFP level, and abdominal ultrasound. Contrast-enhanced CT or MRI was performed when tumor recurrence was clinically suspected. The diagnostic criteria for tumor recurrence were the same as for the initial diagnosis. The follow-up was censored on 31st October 2018.

The end-points of the study were overall survival (OS) and recurrence-free survival (RFS). OS was defined as the interval between the date of surgery and the date of patient death or the date of last follow-up. RFS was the interval between the date of surgery and the date when tumor recurrence was diagnosed or the date of patient death or the date of last follow-up.

Statistical Analysis

The age cut-off of 40 years was based on previous studies.^{2,12,13,22–25} We defined young patients as aged ≤40 years and older patients as aged >40 years. The clinicopathological features and the prognosis in young patients were compared with those in older patients.

Categorical variables were grouped on the basis of a normal reference value or clinical judgment. The albumin-bilirubin (ALBI) grade was calculated by the formula, 0.66 × log₁₀ (bilirubin, μmol/L)-0.085(albumin, g/l).²⁶ According to previously described cut-off resulting in 2 grades: ALBI grade 1 (≤-2.60), grade 2 (>-2.60 to-1.39) and grade 3 (>-1.39). ALBI grade 2 and ALBI grade 3 were group together due to the low sample size in the latter. The results were compared using the chi-square test or Fisher exact test. Continuous variables were compared using the Student’s t-test or Mann–Whitney U-test for variables with an abnormal distribution.

Kaplan-Meier method was used to estimate OS and RFS rates, and the difference between the two groups was analyzed by the Log rank test. Univariate and multivariate Cox proportional hazard regression was performed to detect the independent factors of OS and RFS. Subgroup analysis was conducted based on the univariate Cox model and the forest plot of subgroup analysis was depicted with each estimated HRs and 95% CI. All statistical tests were 2-tailed and a p-value of less than 0.05 was considered statistically significant. All statistical analysis was performed with R version 3.5.2 (http://www.r-project.org/).

Results

Comparison of Clinicopathological Features Between Young and Older HBV-Related HCC Patients

During the study period, there were a total of 6028 patients with HBV-related HCC who received curative resection. 1524 patients were excluded because of extrahepatic metastasis (n=207), preoperative anticancer treatment (n=464), history of other malignancies (n=56), palliative tumor resection (n=174), recurrent tumor resection (n=256), incomplete clinical data (n=80), perioperative death (n=33), and early lost to follow-up after discharge (n=254). Finally, the study consisted of 4504 patients, which comprises 699 young HCC patients and 3805 older HCC patients. The flow chart of this patient selection is shown in Figure 1.

Figure 1 The flow chart of selected patients. Abbreviations: HBV, hepatitis B virus; HCC, hepatocellular carcinoma.

As summarized in Table 1, young patients had higher serum albumin levels (p<0.001), higher platelet counts (p<0.001), better ALBI grade (p<0.001), and lower rates of liver cirrhosis (p=0.001) than older patients. Considering tumor factors, young patients had higher rates of elevated serum AFP levels (p<0.001), larger tumor size (p<0.001), higher rates of microvascular invasion (p<0.001) and macrovascular invasion (p<0.001), higher rates of Edmondson grade III–IV (p=0.01), lower rates of tumor capsular (p=0.025), more advanced AJCC TNM stages (p<0.001) and more advanced BCLC stages (p<0.001) than older patients.

Table 1 Comparison of Clinicopathological Features Between Young and Older HBV-Related HCC Patients

Comparison of Prognosis Between Young and Older HBV-Related HCC Patients

The prognosis after liver resection for HBV-related HCC between young and older patients is shown in Figure 2. The overall survival rates at 1, 3, 5 years were 81.2%, 61%, and 45.3%, respectively, in young patients with HCC and 86.4%,65.3%, and 47.7%, respectively, in the older patients with HCC (p=0.0091, Figure 2A). The recurrence-free survival rates at 1, 3, 5 years were 54.7%, 39.7%, and 28.2%, respectively, in young group and 63.8%, 41.1%, and 28%, respectively, in the older group (p=0.045, Figure 2B).

Figure 2 Comparison of prognosis between young and older groups. (A) OS in the entire patients; (B) RFS in the entire patients; (C) OS in BCLC 0/A staging; (D) RFS in BCLC 0/A staging; (E) OS in BCLC B staging; (F) RFS in BCLC B staging; (G) OS in BCLC C staging; (H) RFS in BCLC C staging. Abbreviations: OS, overall survival; RFS, recurrence-free survival; BCLC, Barcelona Clinic Liver Cancer.

To stratify by tumor factors and liver functional reserve, we performed several subgroup analyses of OS and RFS (Figures 3 and 4, respectively). After stratification by the BCLC staging system, there were no significant differences in OS and RFS between young and older groups in BCLC 0/A staging (p=0.17; p=0.8) and BCLC B staging (p=0.26; p=0.58) (Figure 2C–F). In BCLC C staging, young HCC patients had a significantly worse prognosis than older HCC patients (p=0.018; p=0.00017) (Figure 2G and H).

Figure 3 Subgroup analysis of overall survival between young and older groups. Abbreviations: AFP, alpha-fetoprotein; ALBI grade, albumin-bilirubin grade; BCLC, Barcelona Clinic Liver Cancer; AJCC, American Joint Committee on Cancer; TNM, tumor, node, metastases; HR, hazard ratio; CI, confidence interval.

Figure 4 Subgroup analysis of recurrence-free survival between young and older groups. Abbreviations: AFP, alpha-fetoprotein; ALBI grade, albumin-bilirubin grade; BCLC, Barcelona Clinic Liver Cancer; AJCC, American Joint Committee on Cancer; TNM, tumor, node, metastases; HR, hazard ratio; CI, confidence interval.

Risk Factors Associated with OS and RFS in Young HBV-Related HCC Patients

The univariate and multivariate Cox analysis for determining the risk factors associated with OS and RFS in young HBV-related HCC patients are shown in Table 2. Multivariate analysis revealed that a serum AFP levels of ≥10ng/mL, a resection margin width of <1cm, a tumor size of ≥5cm, the absence of tumor capsular, and the presence of macrovascular invasion were the independent risk factors associated with mortality (Table 2). A serum ALB level of <35g/L, a tumor size of ≥5cm, the presence of microvascular invasion, and macrovascular invasion were the independent risk factors associated with tumor recurrence by multivariate analysis (Table 2).

Table 2 Univariate and Multivariate Cox Regression for OS and RFS in Young HBV Relate HCC Patients

Discussion

Generally, Hepatocellular carcinoma (HCC) usually occurs in middle-aged and elderly individuals. The age distribution of HCC varies according to geographical location and etiology.²⁷ In areas where hepatitis B infection is endemic, screening programs for HCC in high-risk populations are important to increase the rate of early diagnosis and improve treatment outcome.² Nonetheless, the prevalence of HBV-related HCC in young patients, especially in high-risk populations, has increased.³ However, the prognosis of young patients with HBV-related HCC is controversial. Some authors have found that young patients have better long-term outcomes,^8–10 whereas others have reported that young patients have advanced tumor factors, thereby indicating a poor prognosis.^11,12 Several studies have demonstrated that the long-term outcomes after HCC resection are similar between the two groups.^13–15

The variable conclusions may be attributed to the following two aspects. Firstly, the number of young and older patients with HCC was too small for accurate analysis in these studies.^12,22–24 The present study focused on a relatively small proportion of young and older patients with HBV-related HCC in China, and this population was further restricted to patients who intended to curative hepatic resection with good liver functional reserve. Such strict patient selection could be fully compared the clinical characteristics, outcome, and prognostic factors after hepatectomy of young HCC patients with older HCC patients.

Secondly, the lack of standardization of what cut-off age constituted “young and older HCC”. In some studies, the cut-off was defined as 30 or 40 years, whereas in others below 55 years.^2,10,15,28 The determination of the cut-off age for older HCC patients has also varied in the literature.^28–32 We defined young patients as aged ≤40 years and older patients as aged >40 years. The age cut-off of 40 years was based on previous studies.^{2,10,11,20–23} We believe this allows for more meaningful comparisons with other studies. Besides, the Chinese guidelines for the management of HCC recommend screening of males beginning at age 40.³³ Hence, we were interested in evaluating the prognosis in HBV-related HCC patients below this age threshold.

In the present study, the results demonstrated that young patients had higher serum AFP levels, larger tumor size, higher rates of microvascular invasion and macrovascular invasion, higher rates of Edmondson grade III–IV, lower rates of tumor capsular, more advanced AJCC TNM stages, and more advanced BCLC stages than older patents. Meanwhile, young patients also had worse OS and RFS rate than older patients, which is consistent with previous study.^11,12

Multivariate analysis revealed that a tumor size of ≥5 cm and macrovascular invasion were associated with OS and RFS in young patients, so aggressive tumor factors lead to poor prognosis in young patients. Previous studies have shown young patients diagnosed with HCC more often had symptomatic presentations and were less likely to be identified by surveillance.^2,14 It implies that if tumors could be detected at the early stage by more frequent surveillance and radical treatment is performed, long-term survival can be expected in the young patients.

Conclusions

This multicenter study indicated that young patients had better liver function, more aggressive tumor characteristics, and worse prognosis than older patients. A tumor size of ≥5 cm and macrovascular invasion lead to poor prognosis in young patients.