Is Liver Biopsy the Gold Standard?
Mamta K. Jain, MD, MPH
What are the indications for a liver
biopsy?
• Diagnosis of liver disease
• Assess severity of liver disease
• Assess response to treatment
Hepatitis B
• Initial trials
used pre-treatment and post-treatment biopsy to
assess response to nucleoside therapy
• Knodell index grades histological activity from 0-22
–
–
–
–
Periportal bridging necrosis (0-10)
Focal necrosis (0-4)
Portal inflammation (0-4)
Fibrosis (0-4)
• Treatment response based on 2 point decrease in
necroinflammatory activity
– composed of the first three parameters
– measured (0-18)
Lai et al. New Engl J Med 1998;339:61-8
Hepatitis C
• Clinical trials have used viral response as
primary endpoint
• Liver biopsies pre- and post- treatment were
done for
– Confirmation of chronic hepatitis, r/o other
causes, identify cirrhosis (staging)
– Change in histological activity
• Knodell HAI
• METAVIR
McHutchison et al. New Engl J Med 1998;339:1485-92
Poynard et al. Lancet 1998;352:1426-32
Relationship Between Liver disease Stage and
Fibrosis
• Fibrosis– excess collagen
– Collagen proportion of liver fibrosis correlates with hepatic
venous pressure gradient (HVPG)
– Increasing fibrosis has prognostic value
– Histological assessment of fibrosis is by trichrome or
reticulin stains but does not correlate with quantitative
amount of hepatic collagen
• Fibrosis is part of histologic staging of disease
severity
Germani et al. Histopathology 2010; 57:773-784
Relationship Between Liver Disease Stage and
Fibrosis
• Staging describes features that depend on
architectural changes, not just degree of
fibrosis
• Histopathologic assignment of liver disease
stage is a different process from measurement
of liver fibrosis
• Both measurements are complementary but
are imperfectly correlated
Germani et al. Histopathology 2010; 57:773-784
Size of Liver Biopsy
• Smaller biopsy is associated with greater
sampling error
– Error reduced by increasing sample size and
number of biopsies performed
– Study found 25 mm biopsy had error rate of 25%
– Optimal size 40 mm
• But only 16% of samples are >20 mm
Bedossa et al. Hepatology 2003;38:1449-1457
Sampling Error
• Studies have shown 10-30% of cirrhosis was
understaged by percutaneous liver biopsy
• Study of biopsy of the left and right lobe of
the liver found discrepancy in 50% of the
samples
– Inaccurate by 1 stage
– Underestimation of inflammation
Maharaj et al. Lancet 1986; 1:523-25
Poniachik et al. Gastrointest endosc 1996; 43:568-571
Regev et al. Am J Gastroenterol 2002; 97:2614-2618.
Intra-observer Variability
• Intra-observer variability seen in up to 10% of
samples and was 1 stage or 1 grade.
• Use of scoring system has made staging more
consistent
Regev et al. Am J Gastroenterol 2002; 97:2614-2618.
Complications
• HALT-C reported complications of liver biopsy
in HCV patients with advanced liver disease
– 1.1 % serious adverse events
– 0.6% due to bleeding (most common)
• More common if platelet <60,000
• INR>1.3
Seeff et al. Clin Gastroentrol Hepatol 2010; 8:877--83.
Pro and Cons for Liver Biopsy
Pros
• Steatosis assessment and
quantification
• Fibrosis assessment and
architectural distortion
• Iron level measurement
• Diagnose other pathology
– Using special stains
– other liver disease (viral
hepatitis + NAFLD, EtOH, etc)
Cons
• Invasive
• Risk of complications 1-5%
– Mortality .01% to 0.1%
• Limitations
– Sampling error
– Intra-observer variability
What are the alternatives?
• Radiology
– CT
– MRI
– US
– Hepatic elastography
• Serum markers of fibrosis
– Indirect
– Direct
Pros and Cons for Radiology
Pros
• Non-invasive
• US with Doppler can be
used to support diagnosis of
cirrhosis
Cons
• Insufficient resolution to
detect earlier stages of
fibrosis
• Accuracy 82-88%
Aube et al. J Hepatol 1999; 30:472-478
Gaiani et al. J Hepatol 1997;27:979-985
Hepatic Elastography
• Emerging technology to stage hepatic fibrosis
• Elastography technique measures liver stiffness of
hepatic tissue (FibroScan; Echosens, Paris, France)
• Ultrasound wave that produces elastic shear
– velocity of the shear wave is related to tissue stiffness
– more rigid, the faster the wave travels
• Increased rigidity is marker of progressive fibrosis
Sandrin et al. Ultrasound Med Biol 2003;29:1705-1713.
Liver Fibrosis Measurement of
Stiffness in Patients with HCV
• Pt distribution for
METAVIR fibrosis
stage, activity grade,
and steatosis
• AUROC curve
0.97-0.99
0.91-0.95
0.79-0.81
Ziol et al. Hepatology 2005; 41:48-54.
Liver Stiffness and HVPG
• HVPG– predictor of survival and
decompensation in cirrhotic patients
• Liver stiffness measurement (LSM) predicted
severe portal hypertension in HCV patients
• AUROC curves for prediction of HVPG
– >10mmHg was 0.99
– >12mmHg was 0.92
– LSM Cut-off values 13.6kPa sensitivity 97%
– LSM Cut-off values 17.6kPa sensitivity 94%
Vizzutti et al. Hepatology 2007; 45:1290-97.
Pro and Cons for FibroScan
Pros
• Non-invasive
• Able to assess a much larger
proportion of the liver
• Serial measurements to
evaluate fibrosis
progression
Cons
• Poor performance in mild to
moderate disease
• Cannot be used in
– Patients with ascites
– Morbid obesity (BMI>40)
• Cost
• Cannot distinguish between
stage 0-II or III-IV
Serum Markers of Fibrosis
• Ideal biomarker
– Liver specific
– Independent of metabolic alterations
– Detect fibrosis regardless of cause
– Sensitive enough to distinguish between fibrosis
stages
– Reflective of dynamic changes
Friedman. J Hepatol. 2003; 38 (Suppl 1); S38-S53.
Indirect Markers of Fibrosis
• FibroTest/FibroSure
– Alpha-2 globulin
– Alpha-2 macroglobulin
– Gamma globulin
– Apoliprotein A1
– Gamma-glutamyl
transferase (GGT)
– Total bilirubin
• ActiTest
– Fibrotest +ALT
• Forns index
• APRI
• Fib-4
• AST/ALT ratio
• AST/ALT with plts
Afdhal and Shiffman 2006 www.CCO hepatitis.
FibroTest
• Classifies fibrosis into 1 of 3 categories
– Mild (METAVIR F0-F1)
– Significant (METAVIR F2-F4)
– Indeterminate
• HCV
– Detect F2 or higher stage
• 75% sensitivity
• 85% specificity
• Accuracy 46%
Imbert-Bismut Lancet. 2001;357:1069-1075.
ActiTest
• FibroTest + ALT
– Reflects necro-inflammation and fibrosis
– Better at identifying more advanced fibrosis
associated with histological inflammation
– Meta-analysis of HCV patients found both
FibroTest and ActiTest reliable alternatives for liver
biopsy.
Poynard et al. Comp Hepatol 2004;3:8.
Halfon et al. Am J Gastroenterol. 2006;101:547-555
Forns Test
• Uses 4 common clinical measurements
– Patient age
– Cholesterol level
– Platelet count
– Gamma-glutamyl transpeptidase
• Studies HCV patients to
– 96% NPV in mild fibrosis
– 66% PPV in F2-F4
• Able to accurately exclude mild fibrosis
• Inferior to FibroTest
Forns et al. Hepatology. 2003; 34 (4 pt 1): 986-992.
Thabut et al. Hepatology. 2003:37:1220-1221
APRI
• Uses clinical variables
– ALT and platelet count
– NPV
• Significant fibrosis 86%
• Cirrhosis 98%
– PPV
• Significant fibrosis 88%
• Cirrhosis 57%
– Able to exclude cirrhosis
Wai et al. Hepatology. 2003; 38: 518-526.
Fib-4 Index
• Uses clinical variables
–
–
–
–
Platelets
ALT
AST
Age
• <1.45 NPV 94.7% to exclude severe fibrosis (F3-F4) with
sensitivity 74.3%
• >3.25 PPV significant fibrosis 82% with specificity of 98%
• Fib-4 <1.45 or >3.25 (62% of all cases) was highly correlated
to FibroTest in 92% and 76%
Vallet-Pichard et al. Hepatology. 2007; 46: 32-36.
Indirect Methods
Pros
• Non-invasive
• Less expensive
• Useful in HCV for determining
significant fibrosis (METAVIR
stage F2-F4) when HCV
treatment is recommended
• May be most useful in fibrosis
that is unevenly distributed
Cons
• Not sensitive enough to
distinguish between stages
• Degree of fibrosis does not
linearly correlate with biopsy
stage
• May be better to evaluate for
inflammation (i.e., FibroTest)
Direct Markers
•
•
Measure qualitative and quantitative
changes in extracellular matrix
markers
Markers matrix deposition
– Procollagen type I carboxyterminal peptide
– Procollagen type III aminoterminal peptide
– Tissue inhibitor of
metalloproteinase
– Transforming growth factor-beta
– Collagen type IV
•
•
•
Markers of matrix removal
– Procollagen Type IV C peptide
– Procollagen Type IV N peptide
– Matrix metalloproteinase
Other markers
– Hyaluronic acid
– YkL-40
Combination biomarker assay
– FibroSpect
– ELF
– SHASTA
None of these markers are liver specific and are influenced by metabolism
Afdhal and Shiffman 2006 www.CCO hepatitis.
Is Liver Biopsy a Gold Standard?
• Perhaps it depends on why biopsy is being done
• Yes, if it is :
– To diagnose a disease (excluding viral hepatitis)
– To exclude other concomitant disease
– To measure iron stores
– To quantify steatosis
– To get special stains for diagnosis
– To stage liver disease if fibrosis is evenly distributed
Is Liver Biopsy a Gold Standard?
• No, if it is:
– To determine cirrhosis
– To evaluate for significant fibrosis
– To determine stage if fibrosis is unevenly distributed
– To follow longitudinally
Future
• Hepatitis C
– With new DAA with high SVR rates, perhaps a liver biopsy is not
needed?
Biopsy is not typically performed in genotype 2 and 3 if patient willing
to be treated
– If liver biopsy and elastography are not equivalent, then what impact
does this have on patient characterization in clinical trials?
Clinical trials are using FibroScan in Europe instead of liver biopsy
– Non-invasive tests need to be validated as predictors of poor
outcomes and not just on correlation to liver biopsy stage
• Hepatitis B
– Will we still need biopsy to determine disease activity to assess for
treatment?
May not need biopsy in HIV/HBV who were started on ART with
Truvada (treatment based on viral load and not on biopsy)
Conclusions
• Liver biopsy still plays an important role in
– Diagnosis of some types of liver disease
– Quantification of steatosis
– Measurement of iron stores
– To distinguish between earlier stages of disease
• Fibrosis can be determined by other means
such as elastography or other non-invasive
tests