Liver, Pancreas and Biliary TractInter-observer variability of response evaluation criteria for hepatocellular carcinoma treated with chemoembolization

BackgroundData comparing EASL and mRECIST criteria for response evaluation in treatment of hepatocellular carcinoma are rare. We evaluated inter-observer variability by these two response evaluation criteria in treatment-naïve patients undergoing chemoembolization.MethodsFor 133 patients undergoing chemoembolization, two radiologists independently measured sum of bi-dimensional and uni-dimensional diameters at baseline using both EASL criteria and mRECIST, and their changes on first follow-up for up to 5 target lesions.ResultsConcordance correlation coefficients for sum of bi-dimensional and uni-dimensional diameters at baseline between two observers were 0.992 and 0.988, respectively. However, those for their changes on follow-up were 0.865 and 0.877, respectively. Similarly, mean differences in sum of bi-dimensional and uni-dimensional diameters at baseline between two observers were small; −0.455 and 0.079 cm, respectively. However, mean differences in changes (%) in sum of bi-dimensional and uni-dimensional diameters on first follow-up between observers increased by −9.715% and −9.320%, respectively. Regarding tumour numbers, kappa-value between observers was 0.942. For treatment response (complete or partial response, stable disease and progression), kappa-value was 0.941 by both criteria. When only up to two target lesions were assessed, kappa-value was 1.000 by both criteria.ConclusionsInter-observer agreements using both response evaluation criteria were excellent, especially when up to two targets were assessed.