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Summary

  1. Top of page
  2. Summary
  3. Review Criteria
  4. Introduction
  5. Methods
  6. Results
  7. Discussion
  8. Acknowledgements
  9. Author Contributions
  10. References

The high risk of recurrence in post-operative hepatocellular carcinoma (HCC) highlights the need for an effective adjuvant treatment. A systematic review of randomised controlled trials (RCTs) was performed to evaluate the clinical efficacy of adjuvant adoptive immunotherapy (AIT) for post-operative HCC patients. Electronic (MEDLINE, EMBASE and Cochrane Library databases) and manual searches were conducted throughout May 2011 to identify RCTs evaluating postoperative AIT for patients with HCC. Methodological quality was assessed in accordance with the QUOROM statement. Four RCTs totalling 423 patients met the eligibility criteria. All RCTs reported significantly improved disease-free survival rate or reduced recurrence rate after treating with adjuvant AIT (p < 0.05). The overall survival rates of AIT group are slightly higher than those of the control group in one study. Moreover, AIT was a safe treatment, with fever as the main adverse effects. This study adds to the evidence that postoperative HCC patients treated with adjuvant AIT show an improvement in disease-free survival rate or recurrence rate.


Review Criteria

  1. Top of page
  2. Summary
  3. Review Criteria
  4. Introduction
  5. Methods
  6. Results
  7. Discussion
  8. Acknowledgements
  9. Author Contributions
  10. References

We included all randomised controlled trials (RCTs) of adjuvant adoptive immunotherapy (AIT) for patients suffering from hepatocellular carcinoma (HCC) after searching MEDLINE, EMBASE and Cochrane Library databases from their inception to May 2011, without language restrictions.

Message for the Clinic

Adoptive immunotherapy is one of the most popular types of therapy for malignancy. It is sometimes used as a treatment for HCC. The results of our systematic review provided evidence for the effectiveness of AIT for reducing recurrence of patients with HCC postoperatively.

Introduction

  1. Top of page
  2. Summary
  3. Review Criteria
  4. Introduction
  5. Methods
  6. Results
  7. Discussion
  8. Acknowledgements
  9. Author Contributions
  10. References

As a malignancy with a poor and dismal prognosis, HCC is increasing in frequency in many countries (1,2). Most HCC is attributed to hepatitis B and/or C virus infection and chronic heavy alcohol consumption which lead to cirrhosis of the liver (3). The estimated incidence of new cases each year is more than 650,000 (4,5). Although the biology and natural history of HCC becomes better understood, diagnostic techniques progressed markedly and surgical outcome for HCC has improved, the prognosis for HCC patients yet remains discouraging, with the recurrence of HCC as the main problem postoperatively. After radical resection of HCC, the 5-year recurrence rate is more than 65% (6–8).

It is found that 50% of HCC patients have microvascular invasion before curative resection (9), and 88% have micrometastases at the time of surgery (10). Microvascular invasion and micrometastases probably cause postoperative recurrence, and 50–90% of the postoperative death rate is attributed to tumour relapse (11,12). Thereby, the prevention of postoperative tumour relapse constitutes one of the most important challenges to improve the surgical efficacy after curative therapies (13). At present, there are various forms of adjuvant therapies for HCC. However, these adjuvant therapies for HCC remain undefined (14). So, an innovative and alternative adjuvant therapy for HCC is urgently needed.

With the development of molecular biotechnology and tumour immunology, the basic research and clinical application of AIT have made a lot of progress (15–17). Nowadays, AIT is being actively explored as an alternative therapy for patients with HCC postoperatively. However, no consensus has been reached regarding the effect of adjuvant AIT on the postoperative HCC recurrence. This review evaluates the evidence for the clinical efficacy and safety of AIT as an adjuvant therapy for patients with HCC.

Methods

  1. Top of page
  2. Summary
  3. Review Criteria
  4. Introduction
  5. Methods
  6. Results
  7. Discussion
  8. Acknowledgements
  9. Author Contributions
  10. References

Identification of trials

MEDLINE, EMBASE and Cochrane Library databases were systematically searched until May 2011. Comparative studies were identified using any of the following key words: hepatocellular carcinoma, HCC, hepatic cancer, hepatic tumour, liver tumour, liver cancer, adoptive immunotherapy, cytokine-induced killer cells, tumour-infiltrating lymphocytes, lymphokine-activated killer cells or interleukin-2. The search was not limited to controlled or randomised trials for minimising the chances of missing a study. A manual search of the relevant references was performed to identify other relevant trials. There were no date or language restrictions.

Randomised controlled trials that assessed the effect of AIT for postoperative HCC were included. Studies dealing with liver metastases or postoperative recurrent HCC were excluded. Patients in the control group received no active treatment. The studies identified through the search were independently screened by two authors (JH Zhong and L Ma) for inclusion. Any disagreements were arbitrated by a third author (LQ Li).

Types of outcome measures

The primary outcomes evaluated in this review were overall survival (OS) rate, disease-free survival (DFS) and recurrence rates. The secondary outcome was the adverse effects of treatment/toxicity (including withdrawals and discontinuations).

Quality assessment

This systematic review is conducted in accordance with the Quality of Reporting of Meta-analyses (QUOROM) statement (18). Two authors independently evaluated all included trials based on sequence generation of randomisation, allocation concealment, blinding of outcome assessors and reporting of an intention-to-treat analysis. Trials were considered to be of low quality if they reported none of the items, of moderate quality if they reported on less than three items and of high quality if they reported on three or four items.

Data extraction

Two authors independently extracted data concerning author details, year, methodological quality, number of patients, patients’ characteristics, interventions (i.e. drugs, schedule and number of therapeutic sessions) and outcomes using a data extraction form. Discrepancies were resolved by consensus. When multiple publications of the same trial were identified, data were extracted and reported as a single trial.

Data synthesis

Owing to the clinical heterogeneity (including operation methods, dose and type of cytokines) among studies, meta-analysis was not performed. Information from each study was tabulated and discussed in a narrative review.

Results

  1. Top of page
  2. Summary
  3. Review Criteria
  4. Introduction
  5. Methods
  6. Results
  7. Discussion
  8. Acknowledgements
  9. Author Contributions
  10. References

Description of studies

A total of 431 references were identified. The reference flow is shown in Figure 1. Four RCTs including a total of 423 patients were included (19–22). All of them were from Asia. All patients were diagnosed with HCC with preoperative investigations and/or postoperative pathology. No other HCC treatment was being given to all patients till the recurrence had occurred. Across these four studies, recurrence was measured and assessed in the same way using at least two imaging methods. Important details about the included studies are shown in Table 1. All articles were published between 1995 and 2009. The study by Dong et al. (20) had two treatment groups (three and six courses of therapy) and one control group. Patients in one study had undergone transarterial chemoembolisation (TACE) sequentially combined with radiofrequency ablation (RFA) (21). The follow-up period ranged from 18 months (21) to more than 5 years (20). To compare the efficacy of adjuvant AIT of other studies to the included RCTs, five other studies were systematically reviewed, including two RCTs (23,24), two clinical trials (25,26) and one case report (27). Patients in the control arm of these two RCTs received hepatic resection plus chemotherapy (23) or TACE (24).

image

Figure 1.  Flow chart of articles identified, included and excluded. HCC, hepatocellular carcinoma

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Table 1.   Baseline characteristics of randomised clinical trials included into systematic review
StudyMean follow-up (years)Surgery patternArms of treatment (n)Child-Pugh score A/B (n)Tumor size (cm)Aetiology of liver disease cirrhosis (n)Aetiology of liver disease HBV/HCV (n)
  1. AIT, adoptive immunotherapy; CIK, cytokine-induced killer cells; HBV, hepatitis B virus; HCV, hepatitis C virus; IL-2, interleukin-2; LAK, lymphokine-activated killer cells; NR, not reported in the text; NT, no treatment; RFA, radiofrequency ablation; TACE, transarterial chemoembolization.

Takayama et al. (19)Median 4.4 yearsHepatic resectionIL-2 + Anti-CD3 (76)54/22≥3 : 383515/50
<3 : 38
NT (74)50/24≥3 : 423814/49
<3 : 32
Dong et al. (20)More than 5 yearsHepatic resectionCIK (84)68/16≥5 : 366865/NR
<5 : 48
NT (43)34/9≥5 : 213331/NR
<5:22
Weng et al. (21)Median 1.5 yearsRFA+TACECIK (45)36/9≥5 : 28NRNR/NR
<5 : 17
NT (40)33/7≥5 : 25NRNR/NR
<5 : 15
Zhou et al. (22)NRHepatic resectionLAK (31)NRNRNRNR/NR
NT (30)NRNRNRNR/NR

Quality of the included RCTs

The risks of bias in the studies included in this systematic review are detailed in Table 2. The methodological quality was moderate in two studies (19,20) and low in the remaining two studies (21,22).

Table 2.   Methodological quality assessment: internal validity of the included randomised studies
StudyRandom allocation (description of procedure)Concealment of random allocationBlinding of persons who assess treatment effectsIntention-to-treat analysis
Takayama et al. (19)++
Dong et al. (20)+
Weng et al. (21)
Zhou et al. (22)

Efficacy

The results of these studies (19–27) are summarised in Table 3. The study by Takayama and co-workers (19) included 150 patients to receive hepatic resection plus lymphocyte infusions or resection alone. After a median follow-up of 4.4 years, AIT decreased the frequency of recurrence by 18% compared with resection alone, and reduced the risk of recurrence by 41%. The 3- and 5-year DFS rate were 48% in the AIT group vs. 33% in the control group (p < 0.05), and 38% in the AIT group vs. 22% in the control group (p < 0.05) respectively. Moreover, the AIT group had significantly longer disease-specific survival. However, the difference in OS rate was not significant. The estimated 3- and 5-year OS rate were 88% compared with 74%, and 68% compared with 62% respectively. Although the follow-up in the study by Dong et al. (20) was 5–7 years, the results indicated that AIT had similar effects on the DFS and OS rates. The 3- and 5-year DFS rates were 31.7% and 23.3% in three courses group; 30.5% and 19.4% in six courses group; and 20.9% and 11.2% in the control group respectively. Statistical significance was found among the treatment groups and the control group. However, there was no statistical significance among the three groups on the OS rate. The 3- and 5-year OS rates were 66.7% and 37.9% in three courses group; 63.8% and 38.1% in six courses group; and 65.2% and 36.9% in the control group respectively. In the study by Weng and colleagues (21), no patient died within 18 months follow-up. The 18-month recurrence rate was 15.6% in the study group compared with 40% in the control group (p < 0.05). Only 1-year recurrence rate was reported in the fourth study (22). The 1-year recurrence rate of the resection plus AIT group was 32% compared with 57% of the resection alone group (p < 0.05).

Table 3.   Results of randomised clinical studies and case reports of adjuvant adoptive immunotherapy for HCC
StudyDrugs and doseOutcomesTreated arm (%)Control arm (%)comments
  1. CIK, cytokine-induced killer cells; DFS, disease-free survival rate; IL-2, interleukin-2; LAK, lymphokine-activated killer cells; OS, overall survival rate; TACE, transarterial chemoembolization.

Included studies
 Takayama et al. (19)5 infusions lymphocytes (IL-2 + Anti-CD3) (7.1 × 1010)5-year DFS rate3822p < 0.05
5-year OS rate6862p > 0.05
 Dong et al. (20)Group I: 41 patients received 3 courses of CIK (1.0 × 1010 to 2.0 × 1010); Group II:43 patients received 6 courses of CIK (1.0 × 1010 to 2.0 × 1010)5-year DFS rate23 and 1911p < 0.05
5-year OS rate38 and 3837p > 0.05
 Weng et al. (21)39 patients received 8 infusions of CIK (1.0 × 1010 to 1.5 × 1010); 6 patients received 10 infusions of CIK (1.0 × 1010 to 1.5 × 1010)1-year recurrence rate930p < 0.05
1.5-year OS rate100100p > 0.05
 Zhou et al. (22)4 infusions of LAK + IL-2 (intramuscular injection every day)1-year recurrence rate3257p < 0.05
Other randomized clinical studies
 Kawata et al. (23)Treatment arm: 12 patients received adriamycin, IL-2 and LAK therapy Control arm: 12 patients received adriamycin therapy3-year DFS rate5025p > 0.05
3-year OS rate7174p > 0.05
 Xie et al. (24)Treatment arm: 21 patients received TACE plus LAK therapy Control arm: 21 patients received TACE therapy3-year recurrence rate5786p < 0.05
3-year OS rate6229p < 0.05
Clinical trial and Case reports
 Ma et al. (25)Radiofrequency ablation + autologous RetroNectin activated killer cellsDuring 7-months follow-up, all the 7 patients were alive without HCC recurrence.
 Wang et al. (26)Hepatic resection + tumor-infiltrating lymphocytes (5.8 × 107)During 16 months follow-up, 1 of the 8 patients had recurrence.
 Takeda et al. (27)Palliative surgery + 7 infusions of LAK (6.9 × 109)The patient survived for 7 years in remission

Other five studies (23–27) generally indicated a trend showing that adjuvant AIT improved the RFS and OS rates after hepatic resection of HCC (Table 3). In one study (23), 3 of 12 patients died in each group during the follow-up. The 3-year DFS rate was relatively higher in the AIT group compared with the control group (50% vs. 25%). In another study (24), there were significantly better 3-year recurrence and OS rates in the TACE plus AIT group compared with the TACE group (57% vs. 86%, 62% vs. 29%).

Adverse events attributable to AIT

The main adverse effects of AIT was fever (persistent or transient), reported by three of four studies (19–21). Among the 205 treated patients, 52 (25.4%) developed fever after cells transfusion, but were well controlled with antipyretic agents. Persistent fever was observed in 5 of 84 (6.0%) patients (20). Although the temperature was lower than 38.5 °C, these five patients failed to fulfil the AIT in accordance with the protocol. Other rare adverse effects included headache, nausea, dizziness, itching and tachycardia. All adverse events were grade 1 or 2 and self-limiting. No patient had any sign of infection, hepatic deterioration, pulmonary symptoms or autoimmune disorder. No treatment-related deaths were reported. No long-dated adverse effects had been observed during the long-term follow-up. However, the pros and cons in terms of AIT for other races are unknown, because all of these four studies were from Asia.

Discussion

  1. Top of page
  2. Summary
  3. Review Criteria
  4. Introduction
  5. Methods
  6. Results
  7. Discussion
  8. Acknowledgements
  9. Author Contributions
  10. References

This systematic review indicates that adjuvant AIT is a promising biotherapy for improving the DFS rate or reducing the recurrence rate in postoperative HCC patients. Although one study (19) demonstrated that AIT seemed to improve the OS rate, further studies are required to assess the impact of AIT on survival. AIT is a safe adjuvant therapy for postoperative HCC patients, with fever as the main adverse effects.

Three types of immunological effector cells, anti-CD3-activated peripheral blood lymphocytes (19), cytokine-induced killer cells (20,21) and lymphokine-activated killer cells (22), were investigated in the four included RCTs. However, compared with the observation group, the positive treatment group with these effector cells could only improve the DFS rate or reduce the tumour recurrence rate, but not the OS rate. AIT might enhance immunological function and eliminate the small intrahepatic metastases, but could not prevent multicentric relapse. Different treatment modalities during the long observational period might affect the long-term results. These two reasons might explain why AIT could not improve the OS rate.

As an alternative treatments based on stimulation of the exquisite specificity of the anti-tumour immune response, AIT involves the transfer of immune effectors that expand and activate ex vivo to a tumour -bearing host (16,28,29). Immunological effector cells include lymphokine-activated killer cells, cytokine-induced killer cells, tumour-infiltrating lymphocytes, cytotoxic T lymphocytes and natural killer (NK) cells, etc. (30,31). These cells possess cytoplasmic granules that are involved in target cell death. HCC patients had some functional deficiency in host adaptive and innate immunity response (32). In addition, the cellular immune function of HCC patients may descend after hepatectomy (33,34). So, immune deficiency really plays an important role in the pathogenesis, progression, recurrence and metastasis of HCC (35,36). Cases of spontaneous regression of HCC suggest that immune mechanisms are significant in the control of HCC (37). Therefore, it seems reasonable to speculate that strengthening and resuming of the postoperative immunological function as soon as possible may be effective for decreasing the recurrence rate. The effector cells of AIT can efficiently improve the immunological status of HCC patients (33,38,39).

The mechanism of NK cell-mediated anti-tumour immune responses in HCC patients has been well explored (40,41). The reduced activity of NK cell is associated with the HCC patients’ prognosis (42). Local hyperthermia and RFA stimulate the activity of NK cell by several means (43,44). The percentage of CD3+CD56+ cells that have anti-HCV and anti-HCC activity (45) is correlated with patient survival (46), and it increases after cytokine-induced killer cell infusion (21). These suggest that RFA plus AIT may further boost the immunological function and reduce the recurrence rate of HCC patients. All patients in the study by Weng et al. (21) underwent TACE sequentially combined with RFA. No patient died during the 18-month follow-up, maybe because it is associated with the improved immunological function. RFA plus AIT may be superior to hepatic resection plus AIT for HCC patients who are suitable to RFA and hepatic resection. On the contrary, AIT inhibits hepatitis B or C virus replication (45,47,48). So, postoperative HCC patients with hepatitis B or C virus infection may obtain additional benefits from AIT.

Nowadays, more and more types of adjuvant therapy to prevent a second HCC are reported. However, no proven survival benefit has been defined. Some multicentre phase III randomised trials indicated that sorafenib, an oral multikinase inhibitor, was effective for the treatment of advanced HCC (49,50). Sorafenib may be an appropriate option for the treatment of postoperative HCC (51,52). Some phase III trials are ongoing to evaluate the efficacy of sorafenib as a new drug in the treatment of HCC.

The conclusions of this systematic review are subject to some limitations. While we minimised publication bias by the inclusion of non-English studies, the number of studies included in this review is small. It may lead to risk of random errors. Another major drawback of the study is that not all the important patients’ characteristics, such as Child–Pugh score, number of hepatitis B or C virus carriers and cirrhosis, have been described. Therefore, an imbalance among the arms cannot be excluded. In addition, the follow-up of some studies has not been taken into account. The randomisation procedure and allocation concealment remained unclear in some studies. There might be risk of selection bias and performance bias. Almost none of the studies performed blinding of the patients or those who assessed outcome data. Lack of blinding may lead to biased estimates of adverse events.

As a result of the limitations above, the conclusions that adjuvant AIT is a promising biotherapy for improving the DFS rate or reducing the recurrence rate should be interpreted with caution. Further trials should be conducted on the basis of overcoming the limitations mentioned above as much as possible. In addition, adequate follow-up and sample size calculation are necessary. Moreover, future trials are needed to assess other important endpoints, such as quality of life, duration of hospital stay and cost-effectiveness. A double-blind multicentre phase III RCT with a large sample size for more definitive results is needed. Finally, owing to the frequent and/or severe adverse effects of some other adjuvant therapies and many patients are with cirrhosis, multi-modality treatment strategy is needed. The combination of interventional therapies with immune-based therapies may be one choice (53).

In conclusion, as a safe adjuvant therapy, AIT seems to be better than hepatic resection or local ablation alone for postoperative HCC patients. Further trials are required because of the risk of limitations.

Acknowledgements

  1. Top of page
  2. Summary
  3. Review Criteria
  4. Introduction
  5. Methods
  6. Results
  7. Discussion
  8. Acknowledgements
  9. Author Contributions
  10. References

We thank Yu-Hua Xie from Indonesia for her language editing of this manuscript, which remarkably improved the quality of this paper. This work was supported by the grant from National Natural Science Foundation of China (Project No.: 30960021/c010803, to Le-Qun Li, PhD).

Author Contributions

  1. Top of page
  2. Summary
  3. Review Criteria
  4. Introduction
  5. Methods
  6. Results
  7. Discussion
  8. Acknowledgements
  9. Author Contributions
  10. References

Jian-Hong Zhong and Le-Qun Li contributed to study concept and design. Jian-Hong Zhong, Liang Ma and Liu-Cheng Wu searched database and extract dada. Wei-Ping Yuan and Fei-Xiang Wu were responsible for statistical methods. Le-Qun Li obtained funding. Jian-Hong Zhong, Liang Ma,Wei Zhao, Zhi-Ming Zhang, Shan Huang and Xue-Mei You drafted the manuscript.

References

  1. Top of page
  2. Summary
  3. Review Criteria
  4. Introduction
  5. Methods
  6. Results
  7. Discussion
  8. Acknowledgements
  9. Author Contributions
  10. References