Patients are divided into groups by level of hepatitis B surface antigen as follows: less than 100 IU/mL (group 1 [n = 280]), 100 to 999 IU/mL (group 2 [n = 342]), and 1000 IU/mL or greater (group 3 [n = 440]). For comparison of survival curves, P = .006, log-rank test.
Patient groups are classified as having low (<1000 IU/mL [n = 622]) and high (≥1000 IU/mL [n = 440]) hepatitis B surface antigen (HBsAg) levels. P = .002, log-rank test.
Patient groups are classified as having low (<1000 IU/mL [n = 622]) and high (≥1000 IU/mL [n = 440]) hepatitis B surface antigen (HBsAg) levels. P = .004, log-rank test.
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Huang G, Lau WY, Zhou W, et al. Prediction of Hepatocellular Carcinoma Recurrence in Patients With Low Hepatitis B Virus DNA Levels and High Preoperative Hepatitis B Surface Antigen Levels. JAMA Surg. 2014;149(6):519–527. doi:10.1001/jamasurg.2013.4648
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In patients with low viral loads, high levels of hepatitis B surface antigen (HBsAg) have been shown to predict development of hepatocellular carcinoma (HCC). Whether high levels of HBsAg increase the risk for HCC recurrence after hepatic resection remains unknown.
To investigate the association between levels of HBsAg and the risk for tumor recurrence after curative resection in HCC patients with low levels of hepatitis B virus (HBV) DNA.
Design, Setting, and Participants
We performed a retrospective analysis of the clinical data of 1062 patients with low HBV DNA levels (<200 IU/mL) who underwent partial hepatectomy for HCC. In particular, we investigated the association between levels of HBsAg and recurrence of HCC.
Partial hepatectomy for HCC.
Main Outcomes and Measures
The risk for first tumor recurrence between patients with high and low HBsAg levels. We calculated cumulative incidences and hazard ratios after adjusting for competing mortality.
The risk for tumor recurrence increased with HBsAg levels of 1000 IU/mL or greater. When we compared the groups with low (<1000 IU/mL) and high (≥1000 IU/mL) HBsAg levels, the 5-year disease-free survival rate (46.1% vs 34.1% [P = .002]) and the overall survival rate (57.5% vs 48.8% [P = .004]) were better in the group with low HBsAg levels. On multivariate analysis, hepatitis B e antigen seropositivity, HBsAg level of 1000 IU/mL or greater, tumor size of greater than 5 cm, blood transfusion, surgical margin of less than 1.0 cm, the presence of satellite nodules, and the presence of portal vein tumor thrombus were independent risk factors for HCC recurrence. When compared with hepatitis B e antigen status, HBsAg level better predicted recurrence of HCC.
Conclusions and Relevance
A preoperative HBsAg level of 1000 IU/mL or greater is an independent risk factor for HCC recurrence in patients with low HBV DNA levels.
Hepatocellular carcinoma (HCC) is the fifth most common cancer and the third most common cause of cancer-related death in the world.1 Hepatic resection is a well-accepted therapy for HCC, but high postoperative tumor recurrence remains a major obstacle for long-term survival.2 A 2008 study3 found a high serum level of hepatitis B virus (HBV) DNA to be an important predictor of recurrence. Although patients with HBV DNA levels of less than 2000 IU/mL are usually designated as inactive or low-risk HBV carriers,4,5 the postoperative tumor recurrence rate among these patients is still high.6 Since 2010, hepatitis B surface antigen (HBsAg) quantification has become recognized increasingly as a marker for evaluating viral replication and possible host immune control over HBV infection.7-9 However, few studies have evaluated HBsAg level as a predictor of postoperative recurrence of HCC, especially in patients with low HBV DNA levels. The primary aim of this study was to assess the significance of HBsAg level in predicting postoperative HCC recurrence in patients with low HBV load.
This retrospective study was conducted in patients with HBV-related HCC who underwent partial hepatectomy at the liver unit of the Eastern Hepatobiliary Surgery Hospital from January 1, 2006, through December 31, 2007. Patients who were seropositive for HBsAg with a low preoperative HBV DNA level were included in this study. Hepatic resection was the first choice of curative treatment for patients with resectable HCC and good liver function. Liver transplant was considered in patients meeting the Milan criteria10 who had poor liver function. However, owing to the shortage of donor organs, transplant was not readily available for these patients. The 97 patients who received a liver transplant in our hospital were excluded from this study. For patients with small HCC (<3 cm and <3 lesions), radiofrequency ablation (RFA) was the procedure of choice if they were not candidates for surgery or had poor liver function when a donor liver was not available. The study was approved by the Ethics Committee of the Eastern Hepatobiliary Hospital; informed consent was not required.
All patients underwent chest radiography, ultrasonography, and intravenous contrast–enhanced computed tomography or magnetic resonance imaging of abdomen. Laboratory blood tests including measurement of HBsAg, hepatitis C virus antibody, serum α-fetoprotein, carcinoembryonic antigen, carbohydrate antigen 19-9, serum albumin, serum total bilirubin, aspartate aminotransferase, and alanine aminotransferase levels and prothrombin time were performed.
Tests for viral replication, including hepatitis B e antigen (HBeAg) and its antibody, were performed. The serum HBV DNA level was quantified by polymerase chain reaction assay (ABI 7300; Applied Biosystems) with a linear range of quantification of 200 to 2 000 000 IU/mL. The lower limit of detection was 200 IU/mL. The HBsAg level was quantified using a commercially available assay (Architect; Abbott Laboratories) with a detection range of 0.05 to 250 IU/mL. If the HBsAg level was greater than 250 IU/mL, samples were diluted from 1:100 to 1:1000 to obtain a reading within the calibration curve range.
The preoperative diagnosis of HCC was based on the diagnostic criteria for HCC used by the European Association for the Study of the Liver.11 Further investigations were performed only when clinical evidence suggested the presence of extrahepatic metastases.
Surgery was performed through a bilateral subcostal incision. The abdominal cavity was searched for extent of local disease, extrahepatic metastases, and peritoneal seeding. Intraoperative ultrasonography assessed the number and the size of the lesions and the relationship of the tumor to vascular structures. The Pringle maneuver was applied to occlude the blood inflow of the liver with cycles of 15 minutes clamped and 5 minutes unclamped. Liver transection was performed using a clamp-crushing method.
The resected tumor and surrounding liver were examined macroscopically and microscopically for histopathologic features. The histologic grade of cirrhosis and inflammation in the nontumorous liver were scored according to the classification of Ishak et al.12Curative resection was defined as complete macroscopic and microscopic removal of the tumor (R0 resection). The presence of satellite formation and vascular permeation in the tumor was determined.
Patients were followed up at monthly intervals within the first postoperative year and then every 3 months. At each follow-up visit, adverse events were documented and blood samples were taken for complete blood cell counts, coagulation profile, renal and liver function tests, and measurement of serum α-fetoprotein, HBsAg, HBeAg and its antibody, and HBV DNA levels. Ultrasonography was performed once every month. Chest radiography and computed tomography or magnetic resonance imaging were performed once every 3 months in the first year after surgery and thereafter at 6-month intervals.
Recurrent lesions were managed aggressively using a multidisciplinary approach that included repeated resection, transarterial chemoembolization (TACE), percutaneous RFA, and percutaneous ethanol injection. The treatment was decided by the pattern of recurrence, liver functional reserve, and general condition of the patient at the time of recurrence. The primary end point of this study was the time from surgery to tumor recurrence. This study was censored on December 31, 2012.
Virologic data were analyzed with conventional clinical variables at the time of partial hepatectomy to identify factors that influenced recurrence using the Cox proportional hazards model. Risk factors contributing to recurrence were investigated by stratified Cox regression analysis. Cumulative recurrence rates were calculated by the Kaplan-Meier method, and differences were compared by the log-rank test. Multivariate analysis was performed by the Cox proportional hazards regression model. Statistical significance was defined as P < .05. Statistical analysis was performed using commercially available software (SPSS, version 18.0, for Windows; SPSS, Inc).
During the study period, partial hepatectomy was performed in 2860 patients with a preoperative diagnosis of HBV-related HCC in our center. We excluded patients who were seropositive for HBsAg and hepatitis C virus antibodies (45 [1.6%]), who did not have a diagnosis of HCC on results of histopathologic examination of the resected specimen (202 [7.1%]), who had early tumor recurrence or metastasis within 1 month of surgery (81 [2.8%]), who died within 1 month of surgery (27 [0.9%]), or who were lost to or unavailable for follow-up within 6 months of surgery (69 [2.4%]).
Compared with a previous study,13 we chose a tougher standard with an HBV DNA level of less than 200 IU/mL as the low level in this study. Of the remaining 2436 patients who were seropositive for HBsAg, 1267 had a low preoperative HBV DNA level. Antiviral therapy was given to 205 of these 1267 patients (16.2%) before HCC was diagnosed or during the study period. Because antiviral treatment can modify the risk for recurrence of HCC, these patients were also excluded from this study. We included 1062 patients who received no adjuvant therapy.
The patients were divided into the following 3 groups according to the following preoperative HBsAg levels: less than 100 IU/mL (group 1), 100 to 999 IU/mL (group 2), and 1000 IU/mL or greater (group 3). The baseline characteristics of these patients are presented in Table 1. Except for the HBeAg seropositivity rate and preoperative serum alanine aminotransferase level, we found no significant difference in the variables among the 3 groups of patients. During a median follow-up of 60 (range, 4- 84) months, 49 patients (4.6%) were lost to or unavailable for follow-up, 605 (57.0%) developed tumor recurrence, and 508 (47.8%) died. For those patients with tumor recurrence, 89 (14.7%) underwent a repeated resection; 332 (54.9%), percutaneous RFA; 15 (2.5%), percutaneous ethanol injection; 43 (7.1%), TACE; 79 (13.1%), percutaneous RFA combined with TACE; and 34 (5.6%), percutaneous ethanol injection combined with TACE. The remaining 13 patients (2.1%) were not given any anticancer treatment because of deteriorating liver function or poor general condition. The prognosis of patients who received no anticancer treatment was extremely poor, probably because of selection of patients with poor conditions. The prognosis of patients who received TACE was significantly worse than that of the patients who received other types of treatment (P < .05), probably because TACE was used in patients with multiple recurrent HCC. No significant difference was observed in survival among the groups of patients who were treated with repeated resection, percutaneous RFA, or percutaneous ethanol injection (P = .09). The 1-, 3-, and 5-year cumulative disease-free survival (DFS) rates were 81.6%, 47.6%, and 41.1%, respectively. The corresponding cumulative overall survival (OS) rates were 94.2%, 67.6%, and 53.9%, respectively. Of the 508 patients who died, 461 (90.7%) died of tumor recurrence; 40 (7.9%), liver failure; 5 (1.0%), complications of portal hypertension; and 2 (0.4%), other causes.
When the patients were divided into the 3 groups according to the preoperative HBsAg level, the 5-year DFS rates were 48.9%, 43.8%, and 34.1%, respectively; the 5-year OS rates were 59.3%, 56.0%, and 48.8%, respectively. The results suggested that lower HBsAg levels resulted in better prognosis (Figure 1). The DFS for groups 1 and 2 was significantly better than that for group 3 (hazard ratio [HR], 0.74 [95% CI, 0.60-0.90; P = .003] and 0.82 [0.68-0.99; P = .03], respectively), but differences between groups 1 and 2 were not significant (0.90 [0.72-1.12; P = .35]). Thus, the risk for HCC recurrence was similar in patients with HBsAg levels of less than 1000 IU/mL (low level), but it increased when the level was 1000 IU/mL or greater (high level). When the patients were divided only into those 2 subgroups, the 5-year DFS rates for the subgroup with low HBsAg levels was significantly better than that for the subgroup with high HBsAg levels (46.1% vs 34.1% [P = .002]) (Figure 2). The 5-year OS rates for the subgroup with low HBsAg levels was also significantly better than that for the subgroup with high HBsAg levels (57.5% vs 48.8% [P = .004]) (Figure 3).
The factors that were significantly associated with a high cumulative risk for tumor recurrence on univariate analysis were entered into multivariate analysis (Table 2). Seropositivity for HBeAg (HR, 1.30 [95% CI, 1.04-1.62; P = .02]), HBsAg levels of 1000 IU/mL or greater (1.23 [1.04-1.44; P = .01]), tumor size of greater than 5 cm (1.34 [1.12-1.59; P = .001]), blood transfusion (1.45 [1.04-2.03; P = .03]), surgical margin of less than 1.0 cm (1.22 [1.03-1.44; P = .02]), the presence of satellite nodules (2.64 [2.04-3.41; P < .001]), and the presence of portal vein tumor thrombus (6.06 [4.57-8.03; P < .001]) were significant factors associated with a high risk for HCC recurrence after partial hepatectomy.
The factors that were significantly associated with a high cumulative risk for death on univariate analysis were entered into multivariate analysis (Table 3). Seropositivity for HBeAg (HR, 1.29 [95% CI, 1.02-1.63; P = .03]), HBsAg level of 1000 IU/mL or greater (1.26 [1.06-1.51; P = .01]), tumor size of greater than 5 cm (1.37 [1.13-1.65; P = .001]), surgical margin of less than 1.0 cm (1.24 [1.04-1.49; P = .02]), the presence of satellite nodules (2.08 [1.58-2.75; P < .001]), the presence of portal vein tumor thrombus (3.36 [2.53-4.45; P < .001]), and based on the classification of Ishak et al,12 inflammation score of greater than 6 (1.32 [1.06-1.64; P = .01]) and fibrosis score of 4 or greater (1.47 [1.23-1.75; P < .001]) were significant factors associated with a high risk for death after partial hepatectomy.
Because the preoperative HBeAg status and HBsAg levels were associated with HCC recurrence, we used the area under the receiver operating characteristic (ROC) curve to compare these 2 predictors. The area under the ROC curve was 0.53 (compared with 0.49-0.56) for HBeAg seropositivity and 0.56 (compared with 0.52-0.59) for HBsAg level. The ROC curve analysis showed HBsAg level to be superior to HBeAg seropositivity in predicting recurrence of HCC in patients who had a low preoperative HBV DNA level.
Of the 1062 patients, 457 developed early HCC recurrence (ie, <2 years after liver resection). On multivariate analysis, tumor size (HR, 1.40 [95% CI, 1.14-1.71; P = .001]), operation time (1.25 [95% CI, 1.01-1.54; P = .04]), blood transfusion (1.58 [95% CI, 1.11-2.26; P = .01]), surgical margin of less than 1.0 cm (1.39 [1.14-1.69; P = .001]), the presence of satellite nodules (2.80 [2.14-3.68; P < .001]), and the presence of portal vein tumor thrombus (5.51 [4.13-7.34; P < .001]) were significantly associated with early tumor recurrence. A high HBsAg level (HR, 1.08 [95% CI, 0.90-1.30; P = .41]) was not associated with a higher risk for early tumor recurrence. However, on analysis of the risk factors associated with late recurrence in the remaining 552 patients (excluding 457 patients with early tumor recurrence and 53 patients without early tumor recurrence who had died or were lost to or unavailable for follow-up within 2 years), a high HBsAg level (HR, 1.93 [95% CI, 1.38-2.70; P < .001]) was an independent risk factor of late tumor recurrence.
Even after curative partial hepatectomy, the risk for tumor recurrence is extremely high.14 Previous studies3,15-17 have shown that high levels of HBV DNA and seropositivity for HBeAg are closely associated with HCC development and recurrence. The challenge is to find a good marker that can predict postoperative prognosis in HCC patients with a low HBV DNA load. Recent advances in HBsAg assay using a quantitative measure have led to the exploration of its potential role in indicating active HBV infection and predicting treatment outcome.18 A recent study19 showed a high HBsAg level (≥1000 IU/mL) can be used as an independent risk factor for HCC development, suggesting that HBsAg level may be used to complement HBV DNA level in predicting HCC recurrence, especially in patients with low HBV DNA levels.
During the 10 years since 2004, HBsAg level has been shown to be a steady, reliable but unspectacular marker of active HBV infection. The HBsAg level was positively correlated with HBV DNA level and with the rate of HBeAg seropositivity.9 However, the correlations have been shown to be lowest at the lowly replicative phase,20 which was consistent with our results. This discrepancy between the levels of HBsAg and HBV DNA at the lowly replicative phase might be caused by an accumulation of integrated viral envelope sequences in infected hepatocytes. Hepatitis B surface antigen is derived mainly from the integrated form of HBV DNA rather than the episomal form.18 In other words, patients with low viremia who have a high HBsAg level might harbor more hepatocytes with HBV integration than those who have a low HBsAg level.
In our study, the factors that might have contributed to HCC recurrence in patients with a low HBV DNA load of less than 200 IU/mL, in addition to tumor factors and surgical factors, include viral factors such as HBeAg seropositivity and HBsAg levels of 1000 IU/mL or greater. On ROC curve analysis, HBsAg level was superior to HBeAg seropositivity in predicting HCC recurrence. Although these observations need to be confirmed in further studies, they can be explained. First, sustained viremia and subsequent active viral replication may contribute to the carcinogenic process. Patients with low HBV DNA levels are not true inactive carriers, and they are still at a considerable risk of developing HCC.13,18,20,21 Previous studies7,22,23 have also indicated that a low HBsAg level was associated with better clinical outcomes, including a higher likelihood of HBsAg loss, a lower risk of HBeAg-seronegative hepatitis, and a sustained viral suppression. As our findings showed, even in patients with an HBV DNA level of less than 200 IU/mL, a high HBsAg level was also a risk factor for tumor recurrence. Therefore, a combination of low HBsAg and HBV DNA levels might allow a more accurate identification of the true inactive and minimal-risk HBV carriers.24,25 The usefulness of the cutoff HBsAg level as reported in our study has been confirmed by a study of patients from Korea and Hong Kong.26 These findings strongly supported the indication of adequate host immune control against HBV infection by a low HBsAg (<1000 IU/mL) level, thus leading to a decrease in the risk for HCC recurrence over time.
Second, the HBsAg level is positively correlated not just with the serum HBV DNA and HBeAg levels,27 but with the HBV covalently closed circular (ccc) DNA level,28-30 which is the viral template for HBV replication in the maintenance of chronic infection and the predominant form of intrahepatic HBV DNA in the late stage.31 A previous study32 found that tumor tissues had a significantly higher level of cccDNA when compared with the nontumor counterpart, and most of the tumor tissues had intrahepatic HBV DNA solely in the form of cccDNA. Thus, cccDNA might play a direct role in hepatocarcinogenesis. A decline in serum HBV DNA level reflects a reduction in viral replication. In contrast, a decline in serum HBsAg level represents a reduction in the translation of messenger RNAs produced from transcriptionally active cccDNA or integrated sequences.18 Thus, HBsAg quantitation provides different but complementary information that may help to characterize an individual’s infection status. Recurrence of HCC in patients with a high HBsAg level might be attributed to increased genomic instability as a result of integrated viral sequences, which play an important role in hepatocarcinogenesis.33
Third, the serum HBV DNA level may fluctuate during the course of chronic infection,34 but the HBsAg level is relatively stable and endurable.35,36 This supposition is supported by results of natural history studies that showed increased survival, lower rates of hepatic decompensation, and decreased frequency of HCC in patients who have cleared their HBsAg.37,38 In addition, in patients with a low HBV DNA level, the dynamic range of HBsAg level is wider than the HBV DNA level. Thus, the HBsAg level is more powerful than the HBV DNA level or HBeAg status to differentiate patients at different risks of HCC recurrence.
Our DFS and OS results are somewhat disappointing. The reason may be that the difference in early tumor recurrence was not significant (P = .41), but the late recurrence rate was significantly different (P < .001) between the groups with low and high HBsAg levels. Therefore, the HBsAg level is primarily associated with late tumor recurrence, and perhaps we will observe an exciting result after the longer follow-up.
The most important finding of this study is that a preoperative HBsAg load of 1000 IU/mL or greater was independently associated with tumor recurrence in patients with a low HBV DNA load. Quantitative measurement of HBsAg level can be used as a new prognostic factor of HCC recurrence after partial hepatectomy in patients with a low HBV DNA level. A future study should examine whether patients with low HBV DNA but high HBsAg levels should receive antiviral treatment.
Accepted for Publication: July 29, 2013.
Corresponding Author: Wei-ping Zhou, MD, PhD, Department of Hepatic Surgery, Eastern Hepatobiliary Surgery Hospital, Shanghai 200438, China (firstname.lastname@example.org).
Published Online: April 2, 2014. doi:10.1001/jamasurg.2013.4648.
Author Contributions: Drs Huang and Zhou had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Huang, Lau, Zhou, Shen.
Acquisition, analysis, or interpretation of data: Huang, Shen, Pan, Yuan, Wu.
Drafting of the manuscript: Huang, Lau, Pan.
Critical revision of the manuscript for important intellectual content: Lau, Zhou, Shen, Yuan, Wu.
Statistical analysis: Lau, Shen, Pan.
Obtained funding: Huang, Zhou, Shen.
Administrative, technical, or material support: Zhou, Shen.
Study supervision: Huang, Lau, Shen.
Conflict of Interest Disclosures: None reported.
Funding/Support: This study was supported by grants 2012ZX10002010 and 2012ZX10002016 from the State Key Project on Infectious Diseases of China; by contract 81201940 from the Science Fund for Creative Research Groups, National Natural Science Foundation of China (NSFC); and by contract 81201555 from the NSFC.
Role of the Sponsor: The funding sources had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.