Interobserver and intraobserver variability in evaluating vascular invasion in hepatocellular carcinoma
Lifang Fan1, Mylinh T Mac, David P Frishberg
1Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, California 90048, USA.
Insights
Pathologists show moderate agreement in identifying vascular invasion in hepatocellular carcinoma (HCC). However, difficult cases lead to inconsistent staging, impacting patient prognosis and treatment decisions.
Area of Science:
- Oncology
- Surgical Pathology
- Hepatology
Background:
- Vascular invasion is a critical staging parameter for hepatocellular carcinoma (HCC).
- Recognition of vascular invasion among pathologists shows significant variability.
- This variability can lead to inaccurate tumor staging and impact patient management.
Purpose of the Study:
- To assess the accuracy and reproducibility of staging hepatocellular carcinoma (HCC) using vascular invasion.
- To evaluate interobserver and intraobserver agreement among pathologists in identifying vascular invasion in HCC specimens.
Main Methods:
- Analysis of interobserver and intraobserver agreement for vascular invasion in 126 HCC liver resections.
- Six pathologists independently reviewed slides twice, using their own criteria.
- Kappa statistic analysis was used to quantify agreement on slide and image evaluations.
Main Results:
- Moderate interobserver agreement was observed (kappa values 0.50 and 0.43).
- Agreement significantly decreased for equivocal cases presented as images (kappa 0.19).
- Moderate intraobserver agreement ranged from 0.23 to 0.56 (mean 0.45).
Conclusions:
- Pathologists can reproducibly identify vascular invasion in many HCC cases.
- Difficult or equivocal cases pose challenges, potentially leading to understaging or overstaging.
- There is a need for a clearer definition of vascular invasion in HCC to improve prognostic assessment and therapeutic decisions.
Background And Aim:
Hepatocellular carcinoma (HCC) is unique in that the presence of vascular invasion significantly changes tumor stage. Even though searching for vascular invasion is a common practice in surgical pathology, there appears to be a great variation among pathologists in its recognition. This study was designed to assess whether HCC could be accurately staged using vascular invasion as a staging parameter.
Methods:
The interobserver and intraobserver agreement for vascular invasion was analyzed in 126 liver resections for HCC. Selected slides were circulated twice among six pathologists for independent review using their own criteria. One to three representative images from 26 equivocal cases selected by one of the authors were re-evaluated by the pathologists. The presence or absence of vascular invasion on each slide or image was recorded as yes or no. The results were analyzed using unweighted kappa statistic analysis for multiple raters.
Results:
The interobserver agreement was moderate on two slide circulations with kappa values of 0.50 (95% confidence interval 0.45-0.55) and 0.43 (0.38-0.47), respectively. The kappa value dropped significantly to 0.19 (0.09-0.29) on selected images photographed from controversial cases. The intraobserver agreement was moderate, with kappa values ranging from 0.23 to 0.56 (mean = 0.45).
Conclusions:
Pathologists can reproducibly recognize vascular invasion in many HCC cases but may have difficulty in equivocal cases, which may lead to either understaging or overstaging of the tumors. This may have a significant impact on prognostic assessment and therapeutic decision making. Our observations indicate the need for improved definition for vascular invasion in HCC.
