Rationale for Screening
Tumor Markers for the Detection of Hepatocellular Carcinoma
        Alpha-fetoprotein
Hepatic Ultrasound
Computed Tomography
Efficacy of Screening and Surveillance Programs

Rationale for Screening

The rationale for screening for hepatocellular carcinoma (HCC) is based on the concept that populations at high risk for HCC, such as those with cirrhosis, can be identified. However, 20% to 50% of patients presenting with HCC have previously undiagnosed cirrhosis.[1,2] These patients would not be recruited into a surveillance program if the presence of cirrhosis is used to define a target population.[3] The modalities potentially available for screening include serum alpha-fetoprotein (AFP) and ultrasonography. Abnormal screening results may lead to liver biopsy for diagnosis. Complications of liver biopsy are reported in 0.06% to 0.32% of patients, and typically occur within the first few hours after the biopsy.

There are four categories of tumor markers that are currently being used or studied for the detection of hepatocellular carcinoma. These include oncofetal antigens and glycoprotein antigens; enzymes and isoenzymes; genes; and cytokines.[4]

Serum AFP, a fetal-specific glycoprotein antigen, is the most widely used tumor marker for detecting patients with HCC. The reported sensitivity of AFP for detecting HCC varies widely in both hepatitis B virus (HBV)-positive and HBV-negative populations, which is attributable to overlap between screening and diagnosis study designs.[3] When AFP is used for screening of high-risk populations, a sensitivity of 39% to 97%, specificity of 76% to 95%, and a positive predictive value (PPV) of 9% to 32% have been reported.[5-9] AFP is not specific for HCC. Titers also rise in acute or chronic hepatitis,[10] in pregnancy, and in the presence of germ cell tumors.

A prospective, 16-year, population-based, observational study of screening for hepatocellular cancer among 1,487 Alaska Natives chronically infected with HBV compared survival among screen-detected HCC patients with a historical comparison group of clinically diagnosed HCC patients.[8] The screening program’s target was AFP determination every 6 months. It achieved 97% sensitivity and 95% specificity (excluding pregnant women) for HCC. Such high sensitivity and specificity have not been found for other high-risk groups, such as individuals with cirrhosis.[11,12] Whether screening actually improved survival is not clear.

Limitations in the sensitivity and specificity of AFP in surveillance of high-risk populations led to the use of ultrasound as an additional method for detection of HCC.[3] Studies in both healthy hepatitis B surface antigen carriers [5] and in patients with cirrhosis [7] have defined the performance characteristics of ultrasound as a screening test for HCC. Sensitivity in the former was 71% and in the latter 78%, with 93% specificity. The PPVs were 14% and 73%, respectively. In a study of patients who were on a waiting list for liver transplantation, ultrasonography was found to have a sensitivity of 58%, a specificity of 94%, a negative predictive value of 91%, and a PPV of 68%.[13]

Limitations in the sensitivity and specificity of AFP and ultrasound in surveillance of high-risk populations, such as individuals with cirrhosis, led to the assessment of computed tomography (CT) as an additional method for detection of HCC. Studies in patients with cirrhosis suggest that CT may be a more sensitive test for HCC than ultrasound or AFP more than 20 μg/L.[11,12]

A controlled trial of 18,816 persons aged 35 to 59 years with hepatitis B in Shanghai randomly assigned patients to a screening group using AFP and ultrasound every 6 months versus a usual care group. HCC mortality was lower in the screened group (83.2 vs. 131.5 per 100,000; mortality rate ratio of 0.63 [95% confidence interval (CI), 0.41–0.98]). While these results are promising, the CI was near 1.0, intention-to-treat analysis was not used, assessment of outcome was not blinded, and generalizability to other populations is uncertain.[14]

A randomized controlled trial studied 5,581 men aged 30 to 69 years who were chronic carriers of HBV between 1989 and 1995 in Qidong County, China. Of these men, 3,712 were randomly assigned to a screening group and 1,869 to a control group. Screening entailed 6-monthly AFP assays, with follow-up of patients having an abnormal (≥20 μg/L) test result. All patients were followed up for liver cancer and/or death. The overall sensitivity and specificity of the program were 55.3% and 86.5%, respectively. In patients who complied with all scheduled screening tests, sensitivity was 80% and specificity was 80.9%. The mortality rate in the screening group (1,138 per 100,000 person-years) was not significantly different from that in the control group (1,114 per 100,000 person-years), although AFP screening resulted in an earlier diagnosis of liver cancer (i.e., percentage of cases in stage I was significantly higher in the screened group [29.0%] than in the control group [6%]).[15]

References

1. Zaman SN, Johnson PJ, Williams R: Silent cirrhosis in patients with hepatocellular carcinoma. Implications for screening in high-incidence and low-incidence areas. Cancer 65 (7): 1607-10, 1990.  [PUBMED Abstract]
   
   
2. Primary liver cancer in Japan. Clinicopathologic features and results of surgical treatment. Liver Cancer Study Group of Japan. Ann Surg 211 (3): 277-87, 1990.  [PUBMED Abstract]
   
   
3. Collier J, Sherman M: Screening for hepatocellular carcinoma. Hepatology 27 (1): 273-8, 1998.  [PUBMED Abstract]
   
   
4. Zhou L, Liu J, Luo F: Serum tumor markers for detection of hepatocellular carcinoma. World J Gastroenterol 12 (8): 1175-81, 2006.  [PUBMED Abstract]
   
   
5. Sherman M, Peltekian KM, Lee C: Screening for hepatocellular carcinoma in chronic carriers of hepatitis B virus: incidence and prevalence of hepatocellular carcinoma in a North American urban population. Hepatology 22 (2): 432-8, 1995.  [PUBMED Abstract]
   
   
6. Oka H, Tamori A, Kuroki T, et al.: Prospective study of alpha-fetoprotein in cirrhotic patients monitored for development of hepatocellular carcinoma. Hepatology 19 (1): 61-6, 1994.  [PUBMED Abstract]
   
   
7. Pateron D, Ganne N, Trinchet JC, et al.: Prospective study of screening for hepatocellular carcinoma in Caucasian patients with cirrhosis. J Hepatol 20 (1): 65-71, 1994.  [PUBMED Abstract]
   
   
8. McMahon BJ, Bulkow L, Harpster A, et al.: Screening for hepatocellular carcinoma in Alaska natives infected with chronic hepatitis B: a 16-year population-based study. Hepatology 32 (4 Pt 1): 842-6, 2000.  [PUBMED Abstract]
   
   
9. Soresi M, Magliarisi C, Campagna P, et al.: Usefulness of alpha-fetoprotein in the diagnosis of hepatocellular carcinoma. Anticancer Res 23 (2C): 1747-53, 2003 Mar-Apr.  [PUBMED Abstract]
   
   
10. Di Bisceglie AM, Hoofnagle JH: Elevations in serum alpha-fetoprotein levels in patients with chronic hepatitis B. Cancer 64 (10): 2117-20, 1989.  [PUBMED Abstract]
    
    
11. Chalasani N, Horlander JC Sr, Said A, et al.: Screening for hepatocellular carcinoma in patients with advanced cirrhosis. Am J Gastroenterol 94 (10): 2988-93, 1999.  [PUBMED Abstract]
    
    
12. Peterson MS, Baron RL, Marsh JW Jr, et al.: Pretransplantation surveillance for possible hepatocellular carcinoma in patients with cirrhosis: epidemiology and CT-based tumor detection rate in 430 cases with surgical pathologic correlation. Radiology 217 (3): 743-9, 2000.  [PUBMED Abstract]
    
    
13. Dodd GD 3rd, Miller WJ, Baron RL, et al.: Detection of malignant tumors in end-stage cirrhotic livers: efficacy of sonography as a screening technique. AJR Am J Roentgenol 159 (4): 727-33, 1992.  [PUBMED Abstract]
    
    
14. Zhang BH, Yang BH, Tang ZY: Randomized controlled trial of screening for hepatocellular carcinoma. J Cancer Res Clin Oncol 130 (7): 417-22, 2004.  [PUBMED Abstract]
    
    
15. Chen JG, Parkin DM, Chen QG, et al.: Screening for liver cancer: results of a randomised controlled trial in Qidong, China. J Med Screen 10 (4): 204-9, 2003.  [PUBMED Abstract]
    
    

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