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Risk factors for the development of hepatocellular carcinoma among patients with chronic hepatitis C who achieved a sustained virological response to interferon therapy
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Study found 4% of sustained viral responders developed liver cancer 3-10 yrs after sustained response was achieved. It's recommended that patients achieving an SVR should continue to be followed with an MRI for at least 5 yrs & for as long as 10 yrs following SVR.
Journal of Gastroenterology and Hepatology
May 2005
HAJIME TOKITA*, HIDEO FUKUI*, AKIHISA TANAKA*, HIROSHI KAMITSUKASA*, MICHIYASU YAGURA*, HIDEHARU HARADA* and HIROAKI OKAMOTO +
*Department of Gastroenterology, National Tokyo Hospital, Tokyo and + Division of Virology, Department of Infection and Immunity, Jichi Medical School, Tochigi-Ken, Japan
INTRODUCTION
In Japan, hepatocellular carcinoma (HCC) is the third leading cause of cancer deaths. Approximately 30 000 patients died of HCC in 2002, and 70-80% of these cases were associated with hepatitis C virus (HCV) infection. It has been demonstrated that HCC frequently develops during the advanced stages of chronic hepatitis C (CHC). Thus, it is considered that preventing the progression of CHC would reduce the risk for developing HCC. Interferon (IFN), administered with or without ribavirin, has been widely used for the treatment of CHC patients. Many investigators have reported that IFN treatment is effective for reducing the serum alanine aminotransferase (ALT) level, reducing and eliminating HCV RNA from the circulation, and improving liver histology in CHC patients. 1-5 There is accumulating evidence that a sustained virological response (SVR) to IFN therapy, defined as the absence of serum HCV RNA at follow-up 6 months after the end of treatment, is highly predictive of long-term remission of the disease. 1-3 Furthermore, the long-term outcome of HCV-infected patients who achieved a SVR to IFN treatment has been shown to be excellent with improvement of liver fibrosis. 1-5 Therefore, it would seem unlikely that patients who have responded to IFN therapy with loss of HCV RNA subsequently develop liver cirrhosis or HCC. However, the development of HCC among CHC patients with a SVR to IFN therapy has been reported. 4-10 Although risk factors for the development of HCC among CHC patients who underwent IFN therapy have been described in previous studies, 4,5, 11-14 it remains unclear as to whether particular subsets of patients with a SVR to IFN therapy should be carefully followed for the early diagnosis of HCC. In the present study, we investigated the risk factors for the development of HCC among CHC patients who had undergone IFN monotherapy and had a SVR.
ABSTRACT
Background and Aim: Hepatitis C virus (HCV)-infected patients who responded to interferon (IFN) treatment with clearance of serum HCV RNA may rarely develop hepatocellular carcinoma (HCC). The aim of the present study was to elucidate the risk factors for liver carcinogenesis among such patients.
Methods: In total, 126 patients with chronic hepatitis C (CHC) who achieved a sustained virological response (SVR) to IFN monotherapy, which was defined as the absence of detectable HCV RNA in the serum at 6 months after completion of treatment, were enrolled and possible risk factors for HCC were analyzed.
Results: During the observation period of 66 ± 36 months after cessation of IFN treatment, five (4.0%) of the 126 patients developed HCC. The cumulative incidence of HCC at 3, 5 and 10 years was estimated to be 0.9, 4.7 and 7.5%, respectively. The cumulative incidence of HCC was significantly higher among patients with severe fibrosis (F3 or F4) than among patients with no or mild fibrosis (F0 to F2) in the liver before treatment (P = 0.007); among patients with alcohol intake of >= 27 g/day than among patients with that of < 27 g/day (P = 0.015); and among patients who were >= 65 years old than among patients who were < 65 years old at the start of treatment (P = 0.026).--- it seems likely that four of five patients who developed HCC in the present study had had undetectable HCC before IFN therapy.
Conclusions: Patients with CHC who had severe fibrosis, who had regularly taken moderate amounts of alcohol, or who were >= 65 years at the start of IFN treatment should be carefully followed to detect small and controllable HCC, even after eradication of HCV.
AUTHOR DISCUSSION
Patients with CHC who have achieved a SVR to IFN treatment are likely to be considered cured. However, the development of HCC in patients who had a SVR to IFN therapy for a long period of time has recently been reported. In these case reports, HCC developed in the CHC patients with a SVR at 72 months, 6 77 months, 9 80 months, 7 and 90 months 10 after the end of IFN therapy. In the present study, five (4.0%) of the 126 patients who had achieved a SVR to IFN therapy developed HCC at 25 months, 42 months, 52 months, 53 months, and 99 months after the end of IFN therapy. Although the growth pattern varies among tumors, the tumor volume doubling time (growth rate) has been estimated to range from 1 to 20 months (median: 6 months), 21 and it has been estimated that the length of time between the occurrence of HCC and the time point at which the HCC tumor has grown to a diameter approximately 1 cm, when it is detectable by conventional US or CT, is more than 72 months. 13 Thus, it seems likely that four of five patients who developed HCC in the present study had had undetectable HCC before IFN therapy. However, it is difficult to distinguish between de novo HCC and HCC that developed before or during IFN therapy. It has been reported that poorer differentiation of a HCC tumor is associated with a shorter doubling time of HCC. 22 Considering the differentiation of the tumor in our five HCC patients, four of the five were moderately differentiated and one was well differentiated. One patient with a SVR in the present study developed moderately differentiated HCC 99 months after the end of IFN therapy. Thus, it is important to investigate the risk factors for the development of HCC among patients with a SVR, separate from those without a SVR.
Many previous studies have revealed various risk factors for the development of HCC among patients with CHC. The risk factors thus far reported are: no history of IFN therapy; 4,11, 23 no response to IFN therapy; 4,5, 11-14 older age; 4,5,11-14,23, 24 male sex; 4,5,12-14,23, 24 past history of blood transfusion; 25 heavy alcohol intake; 21,25, 26 severe fibrosis of the liver; 4,5,11,13,14,25 high histological activity score; 11 portal inflammation; 12 HCV genotype 1b; 24 high HCV RNA level; 12 lower platelet count; 13,14, 23 high serum AFP level; 23 high serum gamma-glutamyl transpeptidase level; 5 low serum albumin level; 25 and high serum ALT level. 23 However, it seems unlikely that all of these risk factors are applicable to patients who have achieved a SVR, for early diagnosis and treatment of HCC, because the incidence of HCC among patients with a SVR is very low compared with that among patients who did not achieve a SVR. 4,5
In the present study, the risk factors for HCC were analyzed among patients with CHC, focusing on those who achieved a SVR to IFN monotherapy, and the following three factors were found to be statistically significant: severe fibrosis (F3 or F4) of the liver before IFN treatment; alcohol intake of 27 g or more per day; and age of 65 years or above at the start of IFN treatment. Of note, a moderate amount of alcohol intake (>=27 g/day) was significantly associated with the development of HCC in patients with a SVR in this study. Although it is well documented that excessive alcohol intake is one of the important risk factors for the development of HCC in patients with CHC, 16,21, 25 the effect of lower levels of alcohol consumption is still unclear. 16 Some investigators have pointed out the effect of light drinking on HCV-associated liver disease. 26-29 In the present study, 15 patients with excessive alcohol intake of >=80 g/day had not developed HCC within the observation period of 26-127 months. This might indicate the existence of a synergistic effect between excessive alcohol intake and other risk factors for HCC. Multivariate analysis (e.g. Cox proportional hazards model) was not performed in this study, because the number of patients who developed HCC were too few (n = 5) to draw a plausible conclusion. Therefore, extended studies are required to determine whether or not these three risk factors are independent risk factors for HCC among CHC patients with sustained loss of serum HCV RNA after completion of IFN treatment.
In the current study, we did not examine HCV RNA in the liver tissues at 6 months after completion of IFN treatment when HCV RNA was not detectable in the circulation. Therefore, we cannot rule out the possibility of HCV persistence in the liver tissues of the five patients who developed HCC. However, the histological findings of non-tumor liver tissues obtained at the time of diagnosis of HCC had improved markedly in each patient as compared with those at baseline.
A weak relationship between positivity of anti-HBc and the development of HCC was observed in the present study, although it was not statistically significant (P = 0.097). The role of resolved or occult HBV infection in promoting the development of HCC in patients with CHC is highly controversial. Some investigators have emphasized its role in hepatocarcinogenesis, 30-32 and others have reported evidence that does not support this. 33,34 Undoubtedly, the accumulation of CHC patients with a SVR who subsequently developed HCC is necessary to elucidate whether or not the presence of isolated anti-HBc is a risk factor for the development of HCC in CHC patients with a SVR.
In Japan, public health insurance has covered IFN alpha-2b plus ribavirin therapy 35 since January 2002 and peginterferon alpha-2a monotherapy 36 since January 2004. Furthermore, combination therapy of peginterferon alpha-2b and ribavirin 37 is now available. These alternative therapies were demonstrated to be more effective than IFN monotherapy in CHC patients with HCV genotype 1 infection, in those with high HCV viral load in the circulation, and in those with severe fibrosis of the liver. 35-37 However, such patients are also at high risk for developing HCC, and it is very likely that the number of patients who develop HCC even after clearance of serum HCV RNA following more effective IFN therapy administered with or without ribavirin, may increase in the future, indicating the necessity of careful follow-up of such patients.
In conclusion, CHC patients who respond to IFN monotherapy or combination therapy should be followed as closely as possible, even after eradication of HCV, paying special attention to those who had severe fibrosis (F3 or F4) in the liver, those who had taken moderate amounts of alcohol (>= 27 g/day), and those who were >= 65 years at the start of IFN treatment, to detect small and controllable HCC.
RESULTS
All patients showed virological clearance and biochemical normalization 6 months after the end of treatment. During the observation period of 66 ± 36 months (range: 7-139 months) after the end of IFN treatment, the sera continued to be negative for HCV RNA in all 126 patients. However, five patients (4.0%) developed HCC. The cumulative incidence of HCC at 3, 5 and 10 years was estimated to be 0.9, 4.7 and 7.5%, respectively. The baseline characteristics of the five patients who developed HCC are presented in Table 2. All five patients who developed HCC were males, whose age ranged from 51 to 70 years at the start of IFN treatment. Four patients were assumed to have contracted HCV infection from a blood transfusion, and one patient was assumed to have contracted HCV infection from home medical therapy. The age at which the five patients were assumed to have contracted HCV infection ranged from 21 to 49 years, and the duration of persistent HCV infection was estimated to be 13-48 years. None of the five patients were heavy drinkers, which was defined as alcohol intake of 80 g or more per day, but four patients (80%) were moderate drinkers who took 27-54 g alcohol per day. The HCV genotype was 1b in one patient, 2a in three patients, and 2b in the remaining patient. Four patients (80%) were positive for anti-HBc but negative for the antibody in the serum diluted at 1:200, indicating that the titer of anti-HBc was too low to support ongoing HBV infection. Furthermore, none had detectable HBV DNA in the circulation. The stage of liver fibrosis at baseline was F3 in four patients (80%) and F2 in the remaining one patient.
The laboratory data at the time of diagnosis of HCC and pathological characteristics of the HCCs in the five patients are presented. HCC was detected 54 ± 27 months (range: 25-99 months) after the end of IFN treatment. Four patients (80%) had a single HCC tumor and one patient (case 3) had three definable tumors. The size of a HCC tumor ranged from 8 to 30 mm in diameter, and the tumor was pathologically diagnosed as 'moderately differentiated' in four patients (80%) and 'well differentiated' in the patient with three tumor nodules (case 3). At the time of diagnosis of HCC, one patient (case 5) had a slightly elevated serum AFP level; however, no other HCC-related markers (AFP-L3 and PIVKA II) were elevated in any of the patients, including case 5. The histological findings of non-tumor liver tissues obtained at the time of diagnosis of HCC had remarkably improved in each patient compared with the histological findings at baseline. The stage of liver fibrosis had improved from F3 to F2 in case 1; from F3 to F1 in cases 2, 3 and 5; and from F2 to F1 in case 4.
Univariate analyses with the Kaplan-Meier method and the log-rank test were performed to compare the cumulative incidence of HCC with regard to various possible risk factors including age at baseline, sex, alcohol intake, laboratory data at baseline (AST, ALT, platelet count, HCV genotype, and anti-HBc) and the degree of liver fibrosis at baseline. These factors were stratified into two groups, and the cumulative incidences of HCC between the two groups were compared. The cumulative incidence of HCC was significantly higher among the 32 patients with severe fibrosis (F3 or F4) than among the 94 patients with no fibrosis (F0) or mild fibrosis (F1 or F2) in the liver tissues before IFN treatment (P = 0.007); among the 42 patients with alcohol intake of >= 27 g per day than among the 84 patients with alcohol intake of < 27 g per day (P = 0.015); and among the 28 patients who were >= 65 years old than among the 98 patients who were < 65 years old at the start of IFN treatment (P = 0.026). In addition, the cumulative incidence of HCC tended to be higher among the 78 males than among the 48 females (P = 0.059), and among the 49 patients with anti-HBc than among the 77 patients without anti-HBc in their sera before IFN treatment (P = 0.097).
METHODS
Patients
In total, 126 histologically proven CHC patients who received IFN treatment at the Department of Gastroenterology, National Tokyo Hospital, between January 1992 and December 2001 and achieved a SVR, were enrolled in this retrospective study. In the present study, a SVR was defined as negativity for detectable HCV RNA in the circulation at 6 months after the end of IFN treatment, using a polymerase chain reaction (PCR) assay with a sensitivity of at least 100 copies (50 IU) per ml. 15,16 The exclusion criteria were as follows: patients with hepatitis B surface antigen, indicating ongoing infection of hepatitis B virus (HBV); patients who were complicated with autoimmune hepatitis; patients who had been diagnosed as having HCC and were cured; and patients with late relapse of HCV infection. No patient had concurrent infection of human immunodeficiency virus type 1. The diagnosis of chronic HCV infection was based on continuous positivity for second-generation antibodies to HCV (Abbott Japan, Tokyo, Japan) and positivity for serum HCV RNA 17 for more than 6 months before IFN treatment was started. All patients underwent liver biopsy just before IFN treatment was started. Histological staging of chronic hepatitis was based on the scoring system proposed by Desmet et al. 18 in which staging is defined as follows: F0 (no fibrosis), F1 (fibrous portal expansion), F2 (bridging fibrosis), F3 (bridging fibrosis with architectural distortion), and F4 (cirrhosis). The 126 patients underwent IFN-alpha monotherapy for 24 ± 3 weeks (range: 9-30 weeks). The total dose of IFN was 722 ± 188 million units (range: 430-980 million units). They received 6-10 million units of IFN-alpha daily for 2-4 weeks, followed by 6-10 million units of IFN-alpha three times a week.
The following parameters were assayed in each patient just before IFN therapy was started: serum levels of aspartate aminotransferase (AST) (normal range: 9-31 IU/L) and ALT (normal range: 4-34 IU/L), platelet count (normal range: 15-30 x 104/µL), antibody against hepatitis B core antigen (anti-HBc, enzyme immunoassay, Abbott Japan), and HCV genotype. When a serum sample was positive for anti-HBc (inhibition percentage >= 70%), the serum diluted at 1:200 was also assayed for anti-HBc. The HCV genotype was determined by the method described previously. 19 This study conforms to the ethical guidelines of the 1975 Declaration of Helsinki and was approved by the Ethics Committee of National Tokyo Hospital. Informed written consent was obtained from each patient.
Follow-up and diagnosis of hepatocellular carcinoma
Follow-up of patients was performed by blood examinations including ALT, AST, qualitative detection of HCV RNA, alpha-fetoprotein (AFP: normal < 10 ng/mL), lectin-reactive AFP (AFP-L3: normal < 15%) and vitamin K absence or antagonist II (PIVKA II: normal range: 0-39 mAU/mL) at regular intervals of within 6 months. Imaging diagnosis was performed at least twice a year by ultrasonography (US) or computed tomography (CT). In all patients studied, serum samples were continuously negative for HCV RNA after the end of IFN treatment using Amplicor HCV v2.0 (Nippon Roche, Tokyo, Japan). The diagnosis of HCC was made using liver imaging (US, CT or magnetic resonance imaging) and/or angiography. In patients whose angiogram did not demonstrate a typical hypervascular image of HCC, microscopic examination of liver specimens obtained by echo-guided fine needle biopsy was performed. Consequently, in all patients with a SVR who developed HCC, a histological diagnosis of HCC was made using surgically resected specimens and/or biopsied specimens.
Detection of hepatitis B virus DNA
The presence of HBV DNA was determined by the method described previously. 20 Briefly, nucleic acids were extracted from 100 µL of serum using a commercially available kit (SMITEST EX-R&D; Genome Science, Tokyo, Japan), and were tested for HBV DNA by nested PCR using primers derived from the well-conserved areas in the S gene region of the HBV genomes of all eight genotypes (A to H) and Perkin-Elmer AmpliTaq DNA polymerase (Roche Molecular Systems, Branchburg, NJ, USA). The first-round PCR (94¡C for 2 min before the start of cycling; 94¡C for 30 s; 55¡C for 30 s; 72¡C for 90 s, with an additional 7 min in the last cycle) was performed for 35 cycles with primers HB095 (sense: 5'-GAG TCT AGA CTC GTG GTG GAC-3') and HB184 (antisense: mixture of two sequences, 5'-CGA ACC ACT GAA CAA ATG GCA CCG C-3' and 5'-CGC ACC ACT GAA CAA ATT GCA C-3'). The second-round PCR for 25 cycles was carried out under the same conditions as the first-round PCR except for extension for 60 s with primers HB097 (sense: 5'-GAC TCG TGG TGG ACT TCT CTC-3') and S2-2 (antisense: 5'-GGC ACT AGT AAA CTG AGC CA-3'). The amplification product of the first-round PCR was 461 base pairs, and that of the second-round PCR was 437 base pairs.
Statistical analyses
The Kaplan-Meier method was used to calculate the cumulative incidence of HCC and the log-rank test was used to compare the cumulative incidence of HCC between two groups. Differences were considered to be statistically significant at P < 0.05. Data are presented as mean ± standard deviation (SD).
"Analysis of hepatocellular carcinoma tumor growth detected in sustained responders to interferon in patients with chronic hepatitis C"
Journal of Gastroenterology and Hepatology
October 2001
Hidenori Toyoda*, Takashi Kumada+, Takashi Honda*, Kazuhiko Hayashi*, Yoshiaki Katano*, Isao Nakano*, Tetsuo Hayakawa* and Yoshihide Fukuda*
Abstract
Background: By analyzing a tumor growth of hepatocellular carcinoma (HCC) detected in sustained responders (SR) to interferon (IFN) therapy for chronic hepatitis C, we sought to determine the duration of follow up in SR that would be sufficient to detect HCC. In addition, we sought to elucidate the presence of HCC, which truly developed after the eradication of hepatitis C virus (de novo HCC development).
Methods: Tumor volume doubling time (DT) was calculated in a total of 46 cases of HCC detected in SR after IFN therapy. Based on DT, the annual growth rate was estimated for each tumor. Survival was compared between patients with HCC <= 30 mm and patients with HCC > 30 mm in diameter.
Results: Doubling time in SR was similar to the previously reported DT of HCC irrespective of IFN therapy. However, extensive DT was observed in three HCCs despite relatively poor differentiation, which may represent de novo HCC development. In the analysis of tumor growth, all HCCs grew to exceed 20 mm in estimated diameter between 6 months and 7 years after the end of IFN therapy. Better survival was observed in patients with HCC <= 30 mm in diameter compared with patients with HCC > 30 mm (P = 0.0107). In surviving patients, recurrences of HCC were very infrequent.
Conclusions: We may be able to detect most HCC in SR between 6 months and 7 years after IFN therapy. However, we cannot neglect the presence of de novo HCC development after the eradication of HCV, which makes it difficult to determine completely sufficient follow-up duration after IFN therapy in this population.
"EDITORIAL
Hepatocellular carcinoma in sustained responders of interferon-treated chronic hepatitis C"
TAKESHI OKANOUE AND YOSHITO ITOH
Third Department of Internal Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
Journal of Gastroenterology and Hepatology
Volume 18 Issue 2 Page 121 - February 2003
See article in J. Gastroenterol. Hepatol. 2002; 17: 1229-35
Chronic hepatitis C virus (HCV) infection is a predominant cause of chronic liver diseases that progresses to hepatocellular carcinoma (HCC) at a high rate in Japan. In fact, 84% of Japanese HCC patients were reported to be seropositive for anti-HCV antibody. 1 Since 1992, patients with chronic HCV infection have been treated with interferon (IFN)-alpha or -beta covered by the public health insurance in Japan. Recently, the IFN monotherapy has been replaced by IFN-alpha-2b plus ribavirin therapy.
The risk factors for HCC development in patients with chronic HCV infection were reported to be male sex, excessive alcohol intake, older age, sporadic infection, advanced histological staging, and lower platelet counts. 2-5 In IFN-treated chronic hepatitis C patients, advanced hepatic fibrosis and decreased platelet counts, reflecting the stage of liver disease, were the significant independent factors for HCC development. 6,7 Interestingly, higher hepatic expression of Fas protein before IFN therapy is also associated with HCC development. 6 Ikeda et al. 8 reported that the hepatocellular carcinogenesis rates in the IFN-treated and -untreated chronic hepatitis C patients were 7.6% and 12.6% at the 10th year, respectively. In particular, the incidence of HCC in sustained responders (SR) was significantly decreased as compared with that in non-responders or patients without IFN therapy. 9-13 In this point, the efficacy of IFN therapy on chronic hepatitis C is superior to that on chronic hepatitis B, because contradictory results exist concerning the efficacy of IFN therapy on hepatocellular carcinogenesis in chronic hepatitis B patients. 14-17
Although a significant decrease in the incidence of HCC in SR to IFN therapy has been observed in addition to improving liver biochemistries, 9-13 HCC is detected in some cases of complete responders (CR) even several years after successful IFN therapy. 18-24 In the previous volume of the Journal, Yamaura et al. reported a case of a CR who developed a small HCC 77 months after the completion of IFN therapy. 21 In this case, interestingly, eradication of HCV was confirmed in the HCC tissue along with the non-tumorous liver tissue or the serum as examined by reverse transcription-polymerase chain reaction for HCV RNA. A similar CR case showing no detectable HCV RNA in the HCC tissue was also reported by Yamaguchi et al. 19 It is reasonable to consider that HCC found in successfully IFN-treated chronic hepatitis C patients after finishing IFN may have already existed in the HCV-infected liver prior to IFN therapy.
Then, how long do the CR/SR patients have to be followed after IFN therapy? More than 40 cases of HCC in CR/SR patients have been reported in Japan, and the interval between the end of IFN therapy and the detection of HCC did not exceed 5 years in 43/46 (93%) of CR/SR 24 or 22/24 (92%) of CR 21 patients. A similar result was observed in our study (unpubl. data, 2000). Therefore, all chronic hepatitis C patients, particularly the male, need to be followed carefully for at least 5 years, even after a successful IFN therapy. In addition, SR/CR patients with moderate or severe liver fibrosis should be followed for at least 10 years because HCC can be detected more than 5 years after finishing IFN therapy. 19,21
It is generally believed that small HCC, particularly those smaller than 1 cm in diameter, are composed of well-differentiated tumor cells, which are often indistinguishable from adenomateous regenerative nodules. 25 When the HCC increases in size, dedifferentiated tumor cells grow in the nodule replacing the well-differentiated tumor cells and progressing to the 'advanced tumor'. 26 In Japan, Majima 27 reported that the doubling time (DT) of HCC less than 3 cm in diameter varied from 14 days to 230 days with the average of 93.0 days by measuring the diameter of the tumor with ultrasonography. This author also commented that dedifferentiated tumors tended to grow rapidly, which was consistent with another report showing that well-differentiated and hypovascular HCC had a significantly longer DT than hypervascular HCC. 28 Ebara et al. 29 reported that the mean DT of HCC less than 3 cm in diameter was 6.5 ± 5.7 months, approximately 195 ± 171 days. Barbara et al., 30 in an Italian population, reported that the mean DT of HCC less than 5 cm in diameter was 204 ± 135 days. Although the DT of HCC varies considerably from case to case, it can be speculated that the mean DT of small, well-differentiated HCC probably exceeds 90 days.
In the process of the development of HCC, many factors affect the growth rate of the tumor, including the apoptosis-inducing agents. We calculated the growth interval between a single HCC cell and a HCC tumor 1 cm in diameter on the assumption that the DT of HCC was 90 days and concluded that it might be more than 6 years. 10 Apart from inhibiting the intrahepatic production of growth-promoting factors for HCC in CR/SR patients, IFN itself may delay the growth of HCC, because IFN has a growth-inhibitory effect. Therefore, the actual mean time for the tumor formation of HCC 1 cm in diameter may be longer than 6 years, and it is reasonable to consider that almost all HCC detected within 10 years of the follow-up period after IFN therapy had already developed prior to IFN therapy.
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