Hepatitis B virus (HBV) is a major public health

Hepatocellular Carcinoma Risk in Chronic Hepatitis B Virus Infected Compensated Cirrhosis Patients With Low Viral Load Dong Hyun Sinn, 1 Junggyu Lee, 1 Juna Goo, 2 Kyunga Kim, 2 Geum-Youn Gwak, 1 Yong-Han Paik, 1 Moon Seok Choi, 1 Joon Hyeok Lee, 1 Kwang Cheol Koh, 1 Byung Chul Yoo, 1 and Seung Woon Paik 1 Controversy exists about whether antiviral therapy (AVT) should be recommended for compensated cirrhosis patients with chronic hepatitis B virus (HBV) infection and detectable, but low, serum HBV-DNA levels. A retrospective cohort of 385 treatmentna ıve, HBV-related compensated cirrhosis patients (mean age: 51.1 6 9.7 years; 66% male) with low HBV-DNA levels (<2,000 IU/mL) was assessed for the development of hepatocellular carcinoma (HCC). During a median of 5.6 years of follow-up, HCC had developed in 37 (9.6%) patients. The 5-year cumulative HCC incidence rate was 2.2%, 8.0%, and 14.0% for patients with undetectable HBV DNA (<12 IU/mL), low HBV- DNA levels plus normal alanine aminotransferase (ALT) levels, and low HBV-DNA levels plus elevated ALT levels at baseline (P 5 0.011). During follow-up, 71 patients maintained undetectable HBV-DNA levels, and 126 experienced HBV-DNA elevation over 2,000 IU/mL. AVT was initiated in 77 patients. In patients without AVT, the 5-year cumulative HCC incidence rates were 13.3%, 8.8%, and 1.4% for those who experienced HBV-DNA elevation, those who maintained detectable, but low, HBV-DNA levels, and those who maintained undetectable HBV-DNA levels, respectively. The 5-year cumulative HCC incidence rate was 5.9% for patients who started AVT; longer AVT duration and longer complete virological response (<12 IU/mL) duration was associated with lower HCC risk. Conclusion: Compensated cirrhosis patients with detectable, but low, viral load were not at low risk for HCC, and AVT was associated with lower HCC risk, suggesting that prompt AVT should be considered for these patients. (HEPATOLOGY 2015;62:694-701) Hepatitis B virus (HBV) is a major public health problem worldwide; roughly 30% of the world s population show serological evidence of current or past infection. 1 Chronic HBV infection can evolve into cirrhosis and/or hepatocellular carcinoma (HCC), 2 and as many as 40% of men and 15% of women with perinatally acquired HBV die of liver cirrhosis or HCC. 1 Unfortunately, there are no effective cures for HBV; currently available treatments, such as interferons (IFNs) and nucleoside/nucleotide analogs (NUCs), can suppress viral replication, but cannot eradicate the virus. 1 Therefore, decision to treat should be individualized based on balancing the risk (i.e., untreated natural course, side effects from treatments, and cost) and benefit of treatment. Opinions differ as to whether patients with compensated cirrhosis (i.e., the early stage of cirrhosis, during which patients experience few or no symptoms) and detectable, but low, serum HBV-DNA levels should undergo antiviral treatment (AVT). Guidelines put forth Abbreviations: AASLD, American Association for the Study of Liver Diseases; AFP, alpha-fetoprotein; ALT, alanine aminotransferase; APASL, Asian Pacific Association for the Study of the Liver; AST, aspartate aminotransferase; AVT, antiviral therapy; CVR, complete virological response; EASL, European Association for the Study of the Liver; HBV, hepatitis B virus; anti-hbe, hepatitis B envelope antibody; HBeAg, hepatitis B envelope antigen; HBsAg, hepatitis B surface antigen; HCC, hepatocellular carcinoma; HR, hazard ratio; IFN, interferon; NUC, nucleoside/nucleotide analog; PH, portal hypertension; RCTs, randomized, placebocontrolled trials; SD, standard deviation. From the 1 Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea; and 2 Biostatistics and Clinical Epidemiology Center, Samsung Medical Center, Seoul, Korea Received November 4, 2014; accepted May 7, 2015. Additional Supporting Information may be found at http://onlinelibrary.wiley.com/doi/10.1002/hep.27889/suppinfo. 694

HEPATOLOGY, Vol. 62, No. 3, 2015 SINN ET AL. 695 by the American Association for the Study of Liver Diseases (AASLD), European Association for the Study of the Liver (EASL), and Asian Pacific Association for the Study of the Liver (APASL) recommend initiating treatment in compensated cirrhosis patients when HBV- DNA levels are high (2,000 IU/mL), irrespective of alanine aminotransferase (ALT) concentration. 3-5 However, for patients with low viral load levels (i.e., an HBV-DNA level <2,000 IU/mL), recommendations vary. EASL guidelines recommend treatment when serum HBV DNA is detectable, 3 whereas APASL guidelines recommend close monitoring. 4 AASLD guidelines recommend treatment when ALT level is elevated, but close monitoring when ALT level is normal. 5 In the present study, we assessed long-term outcomes of compensated patients with cirrhosis with low viral load to assess whether AVT is warranted in these cases. Patients and Methods Study Design, Setting, and Participants. This is a retrospective cohort study of chronic HBV-infected compensated cirrhosis patients who received care at Samsung Medical Center (Seoul, Korea). The study protocol was reviewed and approved by the institutional review board at Samsung Medical Center. Because the study is based on the retrospective analysis of existing administrative and clinical data, the requirement of obtaining informed patient consent was waived by the institutional review board. All patients who had their serum HBV-DNA levels measured using the COBAS TaqMan HBV DNA Test between 2006 (when serum HBV-DNA testing with the COBAS TaqMan HBV DNA Test first began) and 2011 (N 5 21,812) were screened for potential inclusion in the study. The time of this initial HBV-DNA measurement was considered the baseline. We enrolled 465 patients who met all of the following criteria: (1) age 18 years with chronic HBV infection, defined by the presence of hepatitis B surface antigen (HBsAg) in serum for more than 6 months or by clinical history; 2) presence of any of the following clinical indicators of cirrhosis: thrombocytopenia (<150,000 platelets/ml), cirrhotic configuration of the liver (nodular liver surface or caudate lobe hypertrophy) and/or splenomegaly confirmed in imaging studies, or the presence of varices (abnormally enlarged veins, detected by upper endoscopy or cross-sectional images) 6 ; (3) serum HBV-DNA level <2,000 IU/mL for 6 months from baseline; 4) no previous history of IFN or NUC treatment. These 465 patients were further evaluated and excluded from the study if any of following criteria were met: (1) coinfection with hepatitis C virus or human immunodeficiency virus (n 5 5); (2) evidence of decompensated liver as indicated by the presence (or history) of ascites, esophageal or gastric variceal bleeding, hepatic encephalopathy, or a Child-Pugh score 7 (n5 40); (3) follow-up duration of less than 1 year (n 5 31); (4) HCC detected within 1 year of baseline HBV-DNA measurement (n 5 3); or (5) presence of other malignant tumor(s) (n 5 1). Ultimately, a total of 385 patients were included in the study. The primary outcome variable was the diagnosis of HCC during follow-up. The follow-up period was counted as the time elapsed between baseline HBV- DNA measurement and the date of data analysis, which was April 30, 2014. Follow-up assessments were performed on all patients every 3-6 months, or more frequently as required, for a period of at least 1 year. Study Variables. HCC (the primary outcome variable) was diagnosed either by histological evaluation or clinical imaging. 7 Data collected for the following parameters were reviewed to determine study participant eligibility: age; sex; medical history; ultrasonography and upper endoscopy results; serum platelet, hepatitis B envelope antigen (HBeAg), hepatitis B envelope antibody (anti-hbe), and HBV-DNA levels; and other blood chemistry parameters at baseline, including ALT, aspartate aminotransferase (AST), and alphafetoprotein (AFP) levels. A detectable, but low, viral load was defined as a serum HBV-DNA level of 12-1,999 IU/ ml. An elevated ALT level was defined as 34 IU/L for men and 25 IU/L for women, according to previously suggested normal ALT cut-off values for the Korean population. 8 The initial lower limit of 12 IU/mL for HBV-DNA detection was lowered to 9 IU/mL, but for this study, an HBV-DNA level of 12 IU/mL was considered to represent an undetectable HBV-DNA level. Patients were divided into the following three groups based on serum HBV-DNA and ALT levels at baseline: (1) patients with undetectable HBV-DNA levels; (2) Address reprint requests to: Seung Woon Paik, M.D., Ph.D., Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-Gu, 135-710, Seoul, South Korea. E-mail: sw.paik@samsung.com; fax: 182-2-3410-6983. Copyright VC 2015 by the American Association for the Study of Liver Diseases. View this article online at wileyonlinelibrary.com. DOI 10.1002/hep.27889 Potential conflict of interest: Nothing to report.

696 SINN ET AL. HEPATOLOGY, September 2015 Fig. 1. Flow diagram of patients. During follow-up, 71 patients remained in undetectable HBV-DNA levels and 77 started AVT. patients with detectable, but low, viral load (i.e., an HBV-DNA level of 12-1,999 IU/mL) and elevated ALT levels (i.e., 34 IU/L for men and 25 IU/L for women); and (3) patients with detectable, but low, viral load and normal ALT levels. For the entire follow-up period, HBV-DNA levels were usually monitored at 3- to 6-month intervals, and all the data about HBV-DNA levels were collected. Use of AVT (either IFN or NUC) during follow-up was recorded. There were no patients who used IFN during the follow-up period. HBV-DNA elevation above2,000iu/mlwithelevatedaltlevelsatacertain point mostly led to the initiation of AVT, according to the reimbursement policy in Korea. For those who initiated AVT, complete virological response (CVR) was defined by the decrease in serum HBV- DNA to undetectable level (<12 IU/mL). Time to become undetectable HBV DNA (<12 IU/mL) were also assessed. Patients were then divided into the following four groups based on serum HBV-DNA levels and use of AVT during the follow-up period: (1) those who had started AVT; (2) those who did not receive AVT and showed undetectable serum HBV-DNA levels during the entire follow-up period; (3) those who did not receive AVT and had detectable, but low, viral load during the follow-up period (i.e., an HBV-DNA level of 12-1,999 IU/mL); and (4) those who did not receive AVT and experienced an HBV-DNA elevation (e.g., an HBV-DNA level 2,000 IU/mL during follow-up; Fig. 1). Statistical Analysis. Baseline and clinical characteristics were summarized with mean 6 standard deviation (SD) or frequency (percent), as appropriate, and their distributions in controls (no HCC) versus in cases (HCC) were compared by two-sample t test or Fisher s exact test, as appropriate. Cumulative incidence rate of HCC was calculated and plotted by using Kaplan-Meier s method. Log-rank tests were used to examine differences of the incidence rate among the three groups at baseline: (1) undetectable HBV-DNA levels; (2) detectable, but low, viral load plus elevated ALT levels; and (3) detectable, but low, viral load plus normal ALT levels, and among the four groups throughout the follow-up period: (1) received AVT; (2) did not receive AVT and had undetectable HBV-DNA levels; (3) did not receive AVT and had low, but detectable, viral load; and (4) did not receive AVT and had an HBV-DNA elevation. Cox s regression was performed and proportional hazard ratio (HR) was calculated to identify baseline factors associated with HCC risk. We tested potential baseline factors and multivariate analysis was done with variables that showed association in univariate analysis. HCC risk between three groups according to HBV-DNA levels at baseline (undetectable HBV DNA, detectable plus elevated ALT, and detectable plus normal ALT) were assessed. We tested all patients as well as those without AVT during the follow-up period. The risk of HCC according to the changes in serum HBV-DNA levels during follow-up was tested using ageadjusted Cox s regression analysis. HCC risk between

HEPATOLOGY, Vol. 62, No. 3, 2015 SINN ET AL. 697 Table 1. Baseline Characteristics Characteristics All (n 5 385) No HCC (n 5 348) HCC (n 5 37) P Value No AVT (n 5 308) AVT (n 5 77) P Value Age, years, mean 6 SD 51.1 6 9.7 50.7 6 9.5 55.3 6 10.4 0.006 51.8 6 9.8 48.3 6 9.0 0.005 Male, n (%) 252 (66) 228 (66) 24 (65) 0.93 202 (66) 50 (65) 0.91 HBeAg positive, n (%) 37 (10) 15 (4) 3 (8) 0.29 11 (4) 7 (9) 0.063 Cirrhosis, n (%) Thrombocytopenia (<150 3 10 3 /ml) 329 (86) 298 (86) 31 (84) 0.76 266 (86) 63 (82) 0.31 Radiological findings* 204 (53) 184 (53) 20 (54) 0.89 154 (50) 50 (65) 0.019 Varices 77 (27) 68 (26) 9 (32) 0.47 62 (27) 15 (25) 0.71 Child-Pugh score (%) 0.40 0.93 5 346 (90) 314 (90) 32 (87) 277 (90) 69 (90) 6 39 (10) 34 (10) 5 (13) 31 (10) 8 (10) ALT, U/L, median (quartile) 25 (18-36) 25 (18-35) 28 (21-39) 0.27 24 (18-34) 30 (23-43) 0.001 Elevated ALT (%) 130 (34) 115 (33) 15 (41) 0.35 95 (31) 35 (46) 0.015 AST, U/L, median (quartile) 28 (22-36) 28 (22-25) 31 (25-41) 0.028 28 (22-34) 31 (25-39) 0.007 Albumin, mg/dl, median (quartile) 4.2 (4.0-4.4) 4.2 (4.1-4.4) 4.1 (3.9-4.4) 0.14 4.2 (4.0-4.4) 4.2 (4.0-4.3) 0.15 Bilirubin, mg/dl, median (quartile) 1.0 (0.7-1.3) 1.0 (0.7-1.3) 1.0 (0.7-1.2) 0.42 1.0 (0.7-1.3) 1.0 (0.7-1.3) 0.99 Platelet, 310 3 /ml, median (quartile) 127 (100-145) 128 (101-145) 119 (91-144) 0.20 129 (102-145) 120 (95-143) 0.10 AFP, ng/ml, median (quartile) 3.2 (2.4-5.2) 3.2 (2.4-4.9) 3.8 (2.7-8.5) 0.028 3.1 (2.4-4.8) 3.8 (2.7-6.5) 0.003 HBV-DNA levels at baseline 0.006 <0.001 Undetectable, <12 IU/mL (%) 117 (30) 113 (32) 4 (11) 113 (37) 4 (5) Low viral load, 121,999 IU/mL (%) 268 (70) 235 (68) 33 (89) 195 (63) 73 (95) HBV-DNA levels during follow-up (%) 0.091 <0.001 Remained undetectable 71 (18) 69 (20) 2 (5) 71 (23) Remained low viral load 188 (49) 166 (48) 22 (60) 175 (57) 13 (17) Experienced elevation (2,000 IU/mL) 126 (33) 113 (32) 13 (35) 62 (20) 64 (83) *Radiological findings include cirrhotic configuration 6 splenomegaly. Among 291 patients (76%) who had upper endoscopy within 1 year before entry. Among 356 patients (92%) who had serum AFP measurement within 1 month before entry. Elevated ALT is defined for 34 IU/L for men and 25 IU/L for women. patients who remained undetectable HBV DNA, low but detectable HBV-DNA levels, and experienced HBV- DNA elevation were compared for all patients, for those without AVT, and for those with detectable HBV-DNA levels at baseline. Because the time to start AVT or to achieve CVR was different by each individual, and given that AVT treatment and HBV-DNA levels affect one another across time, we used a marginal structural Cox s proportional hazards model to control possible timedependent confounding when we estimated impact of AVT duration or CVR duration on the incidence of HCC. 9 The model included age, peak HBV-DNA levels, and AVT or CVR duration after time-dependent confounding was adjusted by inverse probability-of-treatment weighted estimation. Age and peak HBV-DNA levels were adjusted in this model, given that age is a strong risk factor for HCC and AVT was usually started after experiencing HBV-DNA elevation. Statistical significance was declared when a P value <0.05 and was executed using SAS software (version 9.4; SAS Institute Inc., Cary, NC). Results Baseline Characteristics of Study Participants. Baseline Characteristics of Study Participants. Baseline characteristics of the analyzed patients are shown in Table 1. All enrolled patients had evidence of cirrhosis in the form of thrombocytopenia, cirrhotic configuration with or without splenomegaly, and/or varices, and 331 of 385 (86.0%) had evidence of portal hypertension (PH; thrombocytopenia, splenomegaly, and/or varices). Throughout follow-up (median follow-up duration: 5.6 years; range, 1.0-7.9), HCC was newly diagnosed in 37 patients (9.6%); these patients were older and had higher AST and AFP levels as well as higher frequency of having detectable HBV-DNA level at baseline (Table 1). The detailed HCC characteristics are provided in Supporting Table 1. Stage at diagnosis was Barcelona Clinic Liver Cancer stage 0, A, B, and C for 38%, 46%, 3%, and 13%, respectively. Among baseline factors, age, AFP, and HBV-DNA levels were independent factors associated with development of HCC (Table 2). AVT, in the form of NUC treatment, was initiated in 77 patients (20%) after a median duration of 2.4 years (range, 0.6-6.7); median treatment duration was 3.2 years (range, 0.1-6.6). Patients who began AVT during follow-up had significantly different characteristics from patients who did not undergo treatment (Table 1). Patients who started AVT were younger, had higher frequency of radiological evidence of cirrhosis, and showed higher baseline ALT, AST, and AFP levels. Most patients who started AVT had detectable HBV DNA at baseline (95%) and experienced HBV-DNA elevation during follow-up (83%).

698 SINN ET AL. HEPATOLOGY, September 2015 Table 2. Baseline Risk Factors for HCC Development All (n 5 385) Patients Without AVT During Follow-up (n 5 308) Univariate Multivariate Univariate Multivariate Baseline Factor HR (95% CI) P Value HR (95% CI) P Value HR (95% CI) P Value HR (95% CI) P Value Age (/year) 1.05 (1.02-1.09) 0.004 1.06 (1.02-1.10) 0.002 1.03 (0.99-1.07) 0.074 1.04 (1.01-1.08) 0.045 Male (vs. female) 0.96 (0.49-1.89) 0.91 0.83 (0.39-1.75) 0.63 HBeAg (1) 1.83 (0.56-6.00) 0.31 2.53 (0.60-10.6) 0.20 Child score (6 vs. 5) 1.44 (0.56-3.71) 0.44 1.46 (0.51-4.21) 0.47 ALT (/IU/mL) 1.01 (1.01-1.02) 0.010 1.01 (0.99-1.02) 0.34 1.01 (1.01-1.02) 0.001 1.01 (0.99-1.02) 0.20 AST (/IU/mL) 1.02 (1.01-1.04) <0.001 1.01 (0.98-1.03) 0.35 1.03 (1.01-1.04) <0.001 1.01 (0.98-1.03) 0.34 Albumin (/mg/dl) 0.35 (0.13-0.93) 0.036 0.71 (0.21-2.37) 0.58 0.24 (0.09-0.65) 0.005 0.36 (0.10-1.26) 0.11 Bilirubin (/mg/dl) 0.60 (0.29-1.23) 0.16 0.52 (0.23-1.20) 0.12 Platelet (/310 3 /ml) 0.99 (0.99-1.01) 0.57 0.99 (0.99-1.01) 0.66 AFP (/ng/ml) 1.01 (1.00-1.01) <0.001 1.01 (1.00-1.01) <0.001 1.01 (1.00-1.01) <0.001 1.01 (1.00-1.01) <0.001 Detectable HBV DNA 3.84 (1.36-10.8) 0.011 5.20 (1.53-17.6) 0.008 4.18 (1.46-11.9) 0.008 5.90 (1.66-20.9) 0.006 (vs. undetectable) Normal ALT* 3.32 (1.13-9.77) 0.029 5.52 (1.46-20.7) 0.011 3.08 (1.01-9.37) 0.047 4.74 (1.22-18.4) 0.025 Elevated ALT* 4.88 (1.60-14.8) 0.005 4.99 (1.38-18.0) 0.014 7.16 (2.30-22.2) 0.001 6.98 (1.90-25.6) 0.003 *Adjusted model included age, ALT, AST, albumin, AFP, and HBV-DNA levels. Elevated ALT is defined for 34 IU/L for men and 25 IU/L for women. Abbreviation: CI, confidence interval. HCC Risk as a Function of Baseline HBV-DNA and ALT Levels. The 5-year cumulative HCC incidence rate in patients with detectable, but low, viral load at baseline was significantly higher than that of patients with undetectable serum HBV-DNA levels (10.0% vs. 2.2%; P 5 0.006). Compared to patients with undetectable HBV-DNA levels, those with detectable, but low, viral load had a more than 5 times higher risk for HCC (Table 2). When patients with detectable, but low, viral load were subdivided on the basis of ALT level (i.e., normal vs. elevated), the 5-year cumulative HCC incidence rate was higher for patients with elevated ALT levels, compared to that of patients with normal ALT levels (14.0% vs. 8.0%; P 5 0.28), although the difference was not statistically significant and was higher than patients with undetectable HBV- DNA levels (2.2%; P < 0.001; Fig. 2A). During follow-up, AVT was initiated in 3.4% (4 of 117), 22.2% (39 of 176), and 37.0% (34 of 92) of patients with undetectable, detectable plus normal ALT, and detectable plus elevated ALT, respectively (P < 0.001). Among 308 patients without AVT, the 5-year cumulative HCC incidence rate was 2.4%, 7.6%, and 21.7% for undetectable HBV DNA, detectable plus normal ALT, and detectable plus elevated ALT, respectively (P < 0.001; Fig. 2B). Fig. 2. Risk of HCC as a function of baseline HBV DNA and ALT levels. Patients with detectable, but low, viral load plus elevated ALT levels (group 1) and those with detectable, but low, viral load plus normal ALT levels (group 2) showed higher cumulative incidence of HCC than those with undetectable HBV-DNA levels (group 3). (A) For all patients and (B) for those without AVT during follow-up period.

HEPATOLOGY, Vol. 62, No. 3, 2015 SINN ET AL. 699 Table 4. Impact of AVT on the Development of HCC All (n 5 385) Patients With Detectable HBV DNA at Baseline (n 5 268) Estimate* (95% CI) P Value Estimate* (95% CI) P Value AVT duration 20.22 (20.43 0.01) CVR duration 20.34 (20.61 0.06) 0.038 20.29 (20.51 0.08) 0.018 20.42 (20.71 0.12) 0.008 0.005 *Marginal structural Cox s proportional hazard model, which included age, peak HBV-DNA levels, and AVT duration or CVT duration was used to estimate impact of AVT. Detailed information for the model is shown in Supporting Tables 2-5. Abbreviation: CI, confidence interval. Fig. 3. Risk of HCC as a function of HBV-DNA levels during followup and AVT. Patients who experienced HBV-DNA elevation as well as those who maintained detectable, but low, viral load showed significantly higher cumulative incidence of HCC than those with undetectable HBV-DNA levels. Patients who started AVT during follow-up are also shown. HCC Risk as a Function of HBV-DNA Levels During Follow-up. During follow-up, 71 patients (18%) maintained undetectable HBV-DNA levels, 188 (49%) maintained detectable, but low, viral load, and 126 (33%) experienced an HBV-DNA elevation (2,000 IU/ ml). HBV-DNA elevation occurred more frequently in patients who had detectable, but low, viral load at baseline than in those who had undetectable HBV-DNA levels at baseline (44% vs. 7%; P < 0.001; Fig. 1). In patients without AVT (n 5 308), the 5-year cumulative HCC incidence rate was 1.4%, 8.8%, and 13.3%, respectively, for patients who maintained undetectable HBV-DNA levels (n 5 71), maintained detectable, but low, viral load (n 5 175), and experienced HBV-DNA elevation (n 5 62; P < 0.001; Fig. 3). The risk of HCC in patients who remained detectable, but low, viral load during follow-up was higher than those who remained undetectable HBV-DNA levels, but comparable to those who experienced HBV-DNA elevation (Table 3). Impact of AVT on HCC Incidence. AVT was initiated in 77 patients (20.0%) during follow-up. All AVT was in the form of treatment with NUCs. Entecavir was the most frequently used drug (n 5 58; 75.3%), followed by lamivudine (n 5 14; 18.1%). Clevudine, telbivudine, and adefovir were used in the rest of the patients. There were two cases of drug resistance, in which rescue therapy was applied, and 90.9% (70 of 77 patients) achieved CVR. For patients who began AVT during follow-up, the 5-year cumulative HCC incidence rate was 5.9% (Fig. 3). Because time from study enrollment to initiation of AVT varied from patient to patient, we investigated whether AVT duration (per year) as well as CVR duration (per year) affected HCC incidence. We found that longer AVT duration was significantly associated with lower HCC (Table 4). Furthermore, longer CVR duration was significantly associated with lower HCC incidence as well, with lower estimate than AVT duration (Table 4). This finding was more prominent for patients with detectable HBV DNA at baseline. Detailed data of the model are shown in Supporting Tables 2-5. Discussion In this study, we analyzed the risk of HCC development in compensated cirrhosis patients with detectable, but low, viral load and evaluated whether such patients would benefit from prompt initiation of AVT. Because there are no effective cures for HBV, 1 decision to treat patients should be based on balancing the risk and benefit of the treatment. In South Korea, all populations are reimbursed for health care costs by the national health Table 3. Risk of HCC According to the Changes in Serum HBV-DNA Levels During Follow-up All (n 5 385) Patients Without AVT (n 5 308) Patients With Detectable HBV DNA at Baseline (n 5 268) HBV DNA Levels Age-Adjusted HR (95% CI) P Value Age-Adjusted HR (95% CI) P Value Age-Adjusted HR (95% CI) P Value Remained undetectable Reference Reference Remained low viral load 5.00 (1.17-21.3) 0.029 4.79 (1.11-20.5) 0.035 Reference Experienced elevation 4.83 (1.07-21.6) 0.040 6.07 (1.27-29.0) 0.024 0.89 (0.44-1.82) 0.76 Abbreviation: CI, confidence interval.

700 SINN ET AL. HEPATOLOGY, September 2015 insurance system. Costs of AVT for HBV are covered only if the patient s serum HBV-DNA level is >2,000 IU/mL in patients with cirrhosis; therefore, almost all patients with detectable, but low, viral load are managed to undergo regular monitoring of serum HBV-DNA levels instead of the initiation of AVT. In this study, only 13 patients started AVT at low viral load, and most of patients (93%) who remained in low viral load during the entire follow-up period were followed up without AVT. This situation provides us with a unique opportunity to observe the natural course and outcome of patients with cirrhosis with detectable, but low, viral load. As a result, we found that the risk of developing HCC was not low for patients with low, but detectable, viral load. The 5-year cumulative incidence of HCC was 10.0% for patients with low viral load at baseline. Furthermore, the 5- year cumulative incidence of HCC was still high (8.8%) for patients who remained low viral load for the entire follow-up period. The patients with low, but detectable, HBV-DNA levels at baseline were also at high risk of experiencing HBV-DNA elevation during follow-up. HBV- DNA elevation occurred in 44% of these patients. We also observed the beneficial effect of AVT in these patients. Although the time point of initiation of AVT varied from patient to patient, HCC incidence rate of AVT group was lower than that of patients who maintained detectable, but low, viral load or those who experienced HBV-DNA elevation (Fig. 3). Most of the patients who began AVT achieved CVR, and longer AVT duration or CVR duration was associated with lower HCC risk. CVR duration was more closely associated with HCC risk reduction than AVT duration. Thus, our data suggest that patients with cirrhosis with detectable, but low, viral load should be considered for prompt AVT, as the EASL guideline has suggested. In addition, NUCs are generally safe, well-tolerated oral medications, 10 and long-term NUC therapy has been shown to reverse cirrhosis. 11 Although effective suppression of HBV replication cannot completely eliminate the risk of HCC, 12 NUC treatment has been shown to reduce the incidence of HCC. 12,13 Also, prompt AVT can prevent HBV- DNA elevation during follow-up, which was another factor associated with HCC risk in this study. However, caution is needed in interpreting the benefit of AVT for the following reasons. First, patients who underwent AVT had different baseline characteristics from those who were not treated. Second, AVT was initiated at variable time points during follow-up, which makes proper comparison difficult and would have introduced survivorship bias. Third, patients were mostly treated after experiencing HBV-DNA elevation, so the benefit could be from treating patients who experienced HBV-DNA elevation, and not from treating those who will remain in persistently low detectable HBV-DNA levels. Therefore, to see whether AVT can reduce development of HCC in patients with cirrhosis with persistently detectable, but low, viral load, randomized, placebo-controlled trials (RCTs) are needed, although even RCTs would be limited, given that one cannot accurately identify and include only those who will remain with persistently low detectable HBV-DNA levels at baseline. Therefore, decision to initiate AVT should be individualized, balancing the risk and benefit of the treatment in these patients. As the AASLD guideline suggests, patients with detectable, but low, viral load levels can be further classified into those with elevated or normal ALT levels and managed differently. 5 The AASLD guidelines recommend prompt initiation of AVT for those with elevated ALT levels, but close monitoring for normal ALT levels. 5 HCC risk is associated with ALT level, 14 and ALT level measurement is useful for identifying individuals that could benefit from AVT. 5 In this study, those with elevated ALT were at very high risk for HCC, especially when analysis was limited for those without AVT during follow-up (Fig. 2B). Therefore, as the AASLD guidelines recommend, prompt initiation of AVT for people with elevated ALT levels should be strongly considered. 5 However, in the current study, we also observed that patients with normal ALT levels were not at low risk for HCC. For patients with cirrhosis with high HBV-DNA levels, treatment is usually recommended regardless of ALT level. 2,3,5 This recommendation is based on the well-documented observation that ALT levels can be elevated in patients with normal liver histology 15 and can be normal in patients with cirrhosis. 2,3 ALT levels can be used to identify higher-risk patients; however, given these limitations of the use of elevated ALT as a marker of liver damage, coupled with our finding that patients with cirrhosis with detectable, but low, viral load and normal ALT levels are still at a significant risk for HCC, it may be more prudent to treat patients with cirrhosis regardless of ALT level even those with detectable, but low, viral load levels. The APASL guidelines recommend frequent monitoring for patients with low viral load and treatment for those with HBV-DNA levels >2,000 IU/mL; however, although viral load is associated with HCC, 16 and a decisive factor for treatment, 17 DNA levels can fluctuate, and the cut-off point (2,000 IU/mL) is arbitrarily chosen. 2 Baseline serum HBV-DNA measurements cannot reliably identify patients who will maintain undetectable levels in the future. 18 Progression of liver disease has been previously reported despite low serum HBV-DNA levels. 19 In this study, we observed significant HCC risk in these

HEPATOLOGY, Vol. 62, No. 3, 2015 SINN ET AL. 701 patients, as well as reduced HCC risk by AVT duration. Therefore, for patients with cirrhosis with detectable, but low, viral load, prompt treatment is likely to be a better approach than frequent monitoring. There are some limitations in this study. It should be noted that almost all Korean chronic hepatitis B patients are infected with HBV genotype C, 20 which is known to progress more rapidly to HCC than other genotypes. 2 Therefore, the relevance of our findings to other HBV genotypes remains to be determined. The study has been conducted in the tertiary referral center, which may have introduced selection bias in that more severe cases have been included. Notably, most of the enrolled patients (331 of 385; 86.0%) had evidence of PH, defined by thrombocytopenia, splenomegaly, and/or varices. Generalizability of this finding to patients with cirrhosis without evidence of PH needs to be demonstrated. Last, as previously stated, the retrospective study design is limited to prove benefit of AVT for patients who will show persistently low, but detectable, HBV-DNA levels. Nevertheless, our data well characterize the natural course and outcome of patients with cirrhosis with detectable, but low, viral load. They had higher HCC risk than those with undetectable HBV-DNA levels. HCC risk was higher when ALT levels were elevated, but patients with normal ALT levels were not at low risk for HCC if HBV-DNA level was detectable. Patients with detectable, but low, viral load experienced HBV- DNA elevation frequently, and the risk of HCC was not low even if HBV-DNA levels were maintained at low levels for a long time. In this setting, the address of AVT during follow-up reduced HCC incidence. NUC therapy induced CVR in most of the treated patients, and CVR duration was closely associated with reduced HCC risk. 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Author names in bold designate shared co-first authorship Supporting Information Additional Supporting Information may be found at http://onlinelibrary.wiley.com/doi/10.1002/hep.27889/ suppinfo.