Intermediate fibrosis staging in hepatitis C: a problem not overcome by optimal samples or pathologists' expertise

Area of Science:

• Hepatology
• Pathology
• Medical Diagnostics

Background:

• Accurate staging of liver fibrosis in chronic hepatitis C is crucial for prognosis.
• Limited studies address biopsy performance for intermediate fibrosis, considering sample quality and pathologist variability.
• Chronic hepatitis C fibrosis assessment impacts disease management and treatment decisions.

Purpose of the Study:

• To evaluate the impact of optimal liver specimen criteria (≥ 20 mm and/or ≥ 11 portal tracts) on interobserver agreement for intermediate fibrosis staging.
• To assess the influence of pathologists' expertise on agreement in classifying intermediate fibrosis stages in chronic hepatitis C.
• To determine the reliability of liver biopsy for intermediate fibrosis assessment in chronic hepatitis C.

Main Methods:

• Four pathologists with varying expertise initially scored guided liver biopsies.
• A reference hepatopathologist reviewed biopsies to assess interobserver agreement for fibrosis staging.
• Biopsy specimens were analyzed for fragment length and portal tract count to define optimal samples.

Main Results:

• Optimal liver biopsy samples (240/255) showed overall agreement of 77% (κ = 0.66).
• Interobserver agreement for intermediate fibrosis (F2) was only 42%, varying significantly with pathologist expertise.
• Understaging of fibrosis occurred in 82% of misclassified cases, particularly in the intermediate stage (F2).

Conclusions:

• Liver biopsy exhibits intrinsic limitations for accurately assessing intermediate fibrosis in chronic hepatitis C.
• Optimal sample size and experienced pathologists do not fully resolve agreement issues for intermediate fibrosis.
• Liver biopsy should not be considered the sole gold standard for evaluating intermediate fibrosis in chronic hepatitis C.