Ultrasound screening for hepatocellular carcinoma (HCC) in cirrhosis: the evidence for an established clinical practice

Abdominal ultrasound and alpha-foetoprotein for the diagnosis of hepatocellular carcinoma in adults with chronic liver disease

BACKGROUND

Hepatocellular carcinoma (HCC) occurs mostly in people with chronic liver disease and ranks sixth in terms of global instances of cancer, and fourth in terms of cancer deaths for men. Despite that abdominal ultrasound (US) is used as an initial test to exclude the presence of focal liver lesions and serum alpha-foetoprotein (AFP) measurement may raise suspicion of HCC occurrence, further testing to confirm diagnosis as well as staging of HCC is required. Current guidelines recommend surveillance programme using US, with or without AFP, to detect HCC in high-risk populations despite the lack of clear benefits on overall survival. Assessing the diagnostic accuracy of US and AFP may clarify whether the absence of benefit in surveillance programmes could be related to under-diagnosis. Therefore, assessment of the accuracy of these two tests for diagnosing HCC in people with chronic liver disease, not included in surveillance programmes, is needed.

OBJECTIVES

Primary: the diagnostic accuracy of US and AFP, alone or in combination, for the diagnosis of HCC of any size and at any stage in adults with chronic liver disease, either in a surveillance programme or in a clinical setting. Secondary: to assess the diagnostic accuracy of abdominal US and AFP, alone or in combination, for the diagnosis of resectable HCC; to compare the diagnostic accuracy of the individual tests versus the combination of both tests; to investigate sources of heterogeneity in the results.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Hepato-Biliary Group Diagnostic-Test-Accuracy Studies Register, Cochrane Library, MEDLINE, Embase, LILACS, Science Citation Index Expanded, until 5 June 2020. We applied no language or document-type restrictions.

SELECTION CRITERIA

Studies assessing the diagnostic accuracy of US and AFP, independently or in combination, for the diagnosis of HCC in adults with chronic liver disease, with cross-sectional and case-control designs, using one of the acceptable reference standards, such as pathology of the explanted liver, histology of resected or biopsied focal liver lesion, or typical characteristics on computed tomography, or magnetic resonance imaging, all with a six-months follow-up.

DATA COLLECTION AND ANALYSIS

We independently screened studies, extracted data, and assessed the risk of bias and applicability concerns, using the QUADAS-2 checklist. We presented the results of sensitivity and specificity, using paired forest-plots, and tabulated the results. We used a hierarchical meta-analysis model where appropriate. We presented uncertainty of the accuracy estimates using 95% confidence intervals (CIs). We double-checked all data extractions and analyses.

MAIN RESULTS

We included 373 studies. The index-test was AFP (326 studies, 144,570 participants); US (39 studies, 18,792 participants); and a combination of AFP and US (eight studies, 5454 participants). We judged at high-risk of bias all but one study. Most studies used different reference standards, often inappropriate to exclude the presence of the target condition, and the time-interval between the index test and the reference standard was rarely defined. Most studies with AFP had a case-control design. We also had major concerns for the applicability due to the characteristics of the participants. As the primary studies with AFP used different cut-offs, we performed a meta-analysis using the hierarchical-summary-receiver-operating-characteristic model, then we carried out two meta-analyses including only studies reporting the most used cut-offs: around 20 ng/mL or 200 ng/mL. AFP cut-off 20 ng/mL: for HCC (147 studies) sensitivity 60% (95% CI 58% to 62%), specificity 84% (95% CI 82% to 86%); for resectable HCC (six studies) sensitivity 65% (95% CI 62% to 68%), specificity 80% (95% CI 59% to 91%). AFP cut-off 200 ng/mL: for HCC (56 studies) sensitivity 36% (95% CI 31% to 41%), specificity 99% (95% CI 98% to 99%); for resectable HCC (two studies) one with sensitivity 4% (95% CI 0% to 19%), specificity 100% (95% CI 96% to 100%), and one with sensitivity 8% (95% CI 3% to 18%), specificity 100% (95% CI 97% to 100%). US: for HCC (39 studies) sensitivity 72% (95% CI 63% to 79%), specificity 94% (95% CI 91% to 96%); for resectable HCC (seven studies) sensitivity 53% (95% CI 38% to 67%), specificity 96% (95% CI 94% to 97%). Combination of AFP (cut-off of 20 ng/mL) and US: for HCC (six studies) sensitivity 96% (95% CI 88% to 98%), specificity 85% (95% CI 73% to 93%); for resectable HCC (two studies) one with sensitivity 89% (95% CI 73% to 97%), specificity of 83% (95% CI 76% to 88%), and one with sensitivity 79% (95% CI 54% to 94%), specificity 87% (95% CI 79% to 94%). The observed heterogeneity in the results remains mostly unexplained, and only in part referable to different cut-offs or settings (surveillance programme compared to clinical series). The sensitivity analyses, excluding studies published as abstracts, or with case-control design, showed no variation in the results. We compared the accuracy obtained from studies with AFP (cut-off around 20 ng/mL) and US: a direct comparison in 11 studies (6674 participants) showed a higher sensitivity of US (81%, 95% CI 66% to 90%) versus AFP (64%, 95% CI 56% to 71%) with similar specificity: US 92% (95% CI 83% to 97%) versus AFP 89% (95% CI 79% to 94%). A direct comparison of six studies (5044 participants) showed a higher sensitivity (96%, 95% CI 88% to 98%) of the combination of AFP and US versus US (76%, 95% CI 56% to 89%) with similar specificity: AFP and US 85% (95% CI 73% to 92%) versus US 93% (95% CI 80% to 98%).

AUTHORS' CONCLUSIONS

In the clinical pathway for the diagnosis of HCC in adults, AFP and US, singularly or in combination, have the role of triage-tests. We found that using AFP, with 20 ng/mL as a cut-off, about 40% of HCC occurrences would be missed, and with US alone, more than a quarter. The combination of the two tests showed the highest sensitivity and less than 5% of HCC occurrences would be missed with about 15% of false-positive results. The uncertainty resulting from the poor study quality and the heterogeneity of included studies limit our ability to confidently draw conclusions based on our results.

Apoptosis-inducing antitumor efficacy of hexokinase II inhibitor in hepatocellular carcinoma

Hypoxia stimulates hepatocellular carcinoma (HCC) cell growth via hexokinase (HK) II induction, and alternatively, HK II inhibition induces apoptosis by activating mitochondrial signaling. This study was to investigate whether the induction of HK II by hypoxia is associated with enhanced mitochondrial stability and to confirm the apoptosis-inducing efficacy of HK II inhibitor in an in vivo model of HCC. Mitochondrial stability was examined by treating isolated mitochondria with deoxycholate, a permeability-enhancing agent. Alteration of permeability transition pore complex composition was analyzed by immunoprecipitation and immunoblotting. An in vivo model of HCC was established in C3H mice i.d. implanted with MH134 cells. The antitumor efficacy of i.p. given 3-bromopyruvate (3-BrPA), a HK II inhibitor, was evaluated by measuring tumor volumes and quantifying apoptosis using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining and (99m)Tc-hydrazinonicotinamide-Annexin V scans. Hypoxia enhanced mitochondrial stability, and this was inhibited by 3-BrPA treatment. In particular, HK II levels in permeability transition pore complex immunoprecipitates were reduced after 3-BrPA treatment. In mice treated with 3-BrPA, mean tumor volumes and tumor volume growth were found to be significantly reduced. Moreover, percentages of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling-positive cells were significantly increased in 3-BrPA-treated mice, and this apoptosis-inducing efficacy was reflected in vivo by (99m)Tc-hydrazinonicotinamide-Annexin V imaging. Our results show that hypoxia enhances mitochondrial stability via HK II induction and that HK II inhibitor treatment exhibits an in vivo antitumor effect by inducing apoptosis. Therefore, HK II inhibitors may be therapeutically useful for the treatment of advanced infiltrative hypovascular HCCs, which are growing in a hypoxic environment.

Mass screening of multiple abdominal solid organs using mobile helical computed tomography scanner--a preliminary report

OBJECTIVE

The possibility of a new screening procedure for multiple abdominal solid organs using a mobile helical computed tomography (CT) scanner was evaluated.

METHODS

A total of 4,543 residents, who were 40 years of age or older, received CT scanning without contrast medium. The mean age of participants was 64 years including 2,022 males and 2,521 females.

RESULTS

A total of 2,105 abnormal findings were uniquely detected in 1,594 participants. Liver and kidney diseases including ureter occupied around 30% of total abnormal findings, respectively. Besides frequent cystic or calcified lesions, solid tumours were suspected in 56 lesions, which received further examination by specialized physicians. Five (9%) of them were confirmed as being malignant tumours including pancreatic cancer in two patients, and liver, lung and ovary cancers in one patient each, respectively. All five patients with each malignant lesion received curative operations. Small-sized abdominal aortic aneurysms and heart valve diseases were uniquely found in 22 and two patients, respectively.

CONCLUSION

Qualitative diagnoses of solid tumours were difficult using CT findings without contrast medium. CT screening procedures require further investigation in aspect of the selection of examinees, CT scanning procedure, sensitivity and specificity, and cost-effectiveness.

Alpha-fetoprotein and/or liver ultrasonography for liver cancer screening in patients with chronic hepatitis B

BACKGROUND

Chronic hepatitis B infection may cause liver cancer (hepatocellular carcinoma (HCC)). Alpha-fetoprotein (AFP) and liver ultrasonography (US) are used to screen these patients for HCC. It is uncertain whether screening is worthwhile.

OBJECTIVES

To review randomized trials on screening for HCC with alpha-fetoprotein and/or liver ultrasonography among people with hepatitis B surface antigen (HBsAg) whether asymptomatic or with clinical liver disease.

SEARCH STRATEGY

Relevant reports were searched from electronic databases until August 2002 (The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Controlled Trials Register, MEDLINE, EMBASE, HealthStar, and the Chinese Medical Literature Electronic Databases, MedCyber) supplemented with manual searches on the bibliographies of papers found and communication to people familiar with chronic hepatitis B.

SELECTION CRITERIA

Randomized trials on screening for liver cancer were included irrespective of language. Studies were excluded if the hepatitis B status was uncertain, if patients were not adequately followed, if the screening tests were not sensitive, widely-used ones, or if the test was used for diagnosis rather than screening for HCC.

DATA COLLECTION AND ANALYSIS

We analyzed independently all the studies considered for inclusion. We wrote to the relevant authors for further information. Data were analyzed with Peto's odds ratio (OR) with 95% confidence interval (CI).

MAIN RESULTS

Two trials met the selection criteria. One trial (n = 18,816) compared bi-annual AFP plus US screening with no screening for five years. No data on all-cause mortality were available. The two groups did not differ significantly regarding HCC mortality (OR 0.81; 95% CI 0.54 to 1.22). Number of patients with HCC was significantly increased in the screeened group (OR 1.37; 95% CI 1.00 to 1.88). Most HCCs in the screened group, but none in the control group, were at an early stage. The survival rate of patients with resected HCC in the screened group reached 52.7% after three and five years, but was 0% for those in the control group. The authors' estimated lead-time for HCC was 5.4 months, suggesting that screening prolonged the survival of HCC. Another trial (n = 1069) compared AFP plus US versus AFP screening, but could not decide which approach was superior due to the small sample size (number of detected HCC: OR 0.74; 95% CI 0.26 to 2.12).

REVIEWER'S CONCLUSIONS

There are not enough quality trials to support or refute screening of HBsAg-positive patients for HCC. It is possible that screening may be effective, but also that harm caused by screening/treatment may outweigh any gain. More and better-designed large randomized trials are required.

Liver imaging. A hepatologist's perspective

Numerous diagnostic modalities may be employed in the assessment of liver disease. In this article we outline radiologic approaches to several clinical problems including the evaluation of abnormal liver function tests and jaundice, evaluation of liver masses, and management of the patient with cirrhosis and portal hypertension.

Localized Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) most commonly affects patients with underlying cirrhosis. Screening of cirrhotic patients can result in early detection of HCC. If the tumor is localized to the liver, the patient can be offered therapy. It is our belief that those patients with good liver function (Child-Pugh A/B or better) should be considered for surgical resection of one or two surgical segments of the liver. Otherwise, ablative measures, including radiofrequency ablation (RFA), cryotherapy, or angiographic embolization should be offered to the patient. Alternatively, direct injection of alcohol or acetic acid can result in effective ablation of the lesion, with unclear effects on long-term outcome. Chemotherapy does not appear to impact survival, but it is our belief that combined protocols may offer superior outcomes to single therapeutic interventions. Orthotopic liver transplantation (OLT) can have excellent efficacy in a very select group of patients.

Therapeutic options for HCV--management of the infected individual

Patients with chronic hepatitis C infection should be assessed by liver biopsy prior to consideration of anti-viral therapy. Patients with histologically mild disease should be observed at regular intervals and assessed with a repeat liver biopsy after an interval of 3-4 years. Those with severe disease should receive early treatment with interferon-alpha and ribavirin. The duration of therapy is determined by the genotype of the infecting virus-viral genotypes 2 and 3 require only 6 months of treatment but other genotypes should be treated for 12 months. Approximately 35-40% of treated patients will respond to therapy with a permanent cessation of viral replication and improvement in liver histology. New therapies including polyethylene glycol, PEGylated, interferons and combination regimes involving amantadine are currently under evaluation and it is hoped that improved regimes will be developed in the near future.