Reliability and reproducibility of the Edmondson grading of hepatocellular carcinoma using paired core biopsy and surgical resection specimens

Context: It has been claimed that the Edmondson and Steiner grading system (EGS) values should be obtained preoperatively to select patients with hepatocellular carcinoma for liver transplantation. However, EGS reliability in biopsy specimens has been questioned. Objective: To verify the reliability of the EGS using core biopsy specimens and its reproducibility among pathologists. Design: Paired biopsy and surgical specimens obtained from 40 patients (subset 1) were retrieved by means of computer-aided search of the pathology records and blindly and independently reviewed. The EGS interrater agreement was measured using κ statistics. After having held a consensus meeting, pathologists graded an additional 21 paired hepatocellular carcinoma specimens (subset 2). Results: Analyzing subset 1, pathologists gave significantly lower EGS grades to the biopsy specimens (P <.001), for which the observed agreement was 32.5% (κ = 0.021), which increased to 82.5% (κ = 0.186) if only 2 categories were considered (low grade, EGS I-II; high grade, EGS III-IV). The observed agreement in the case of the surgical specimens was 52.5% (κ = 0.199), which increased to 62.5% (κ = 0.275) when the low-and highgrade scores were merged. The observed agreement between the assessments of paired biopsy and surgical specimens was 50.0% for pathologist 1 (κ = 0.057) and 35.0% for pathologist 2 (κ = 0.078). Merging the EGS grades did not improve the strength of the agreement. Analyzing subset 2 (after the consensus meeting), the observed agreement between pathologists improved more on biopsies (76.2%, κ = 0.614) than on surgical specimens (61.9%, κ = 0.434). Conclusions: The EGS is easily underestimated in core biopsy specimens, and interrater disagreement between pathologists can be significant unless consensus meetings are held.