Radioembolization for hepatocellular carcinoma: Statistical confirmation of improved survival in responders by landmark analyses

Does imaging response predict survival in hepatocellular carcinoma (HCC)? We studied the ability of posttherapeutic imaging response to predict overall survival. Over 14 years, 948 patients with HCC were treated with radioembolization. Patients with baseline metastases, vascular invasion, multifocal disease, Child-Pugh>B7, and transplanted/resected were excluded. This created our homogeneous study cohort of 134 patients with Child-PughB7 and solitary HCC. Response (using European Association for Study of the Liver [EASL] and Response Evaluation Criteria in Solid Tumors 1.1 [RECIST 1.1] criteria) was associated with survival using Landmark and risk-of-death methodologies after reviewing 960 scans. In a subanalysis, survival times of responders were compared to those of patients with stable disease (SD) and progressive disease (PD). Uni/multivariate survival analyses were performed at each Landmark. At the 3-month Landmark, responders survived longer than nonresponders by EASL (hazard ratio [HR], 0.46; confidence interval [CI], 0.26-0.82; P=0.002) but not RECIST 1.1 criteria (HR, 0.70; CI, 0.37-1.32; P=0.32). At the 6-month Landmark, responders survived longer than nonresponders by EASL (HR, 0.32; CI, 0.15-0.77; P<0.001) and RECIST 1.1 criteria (HR, 0.50; CI, 0.29-0.87; P=0.021). At the 12-month Landmark, responders survived longer than nonresponders by EASL (HR, 0.34; CI, 0.15-0.77; P< 0.001) and RECIST 1.1 criteria (HR, 0.52; CI 0.27-0.98; P=0.049). At 6 months, risk of death was lower for responders by EASL (P< 0.001) and RECIST 1.1 (P=0.0445). In subanalyses, responders lived longer than patients with SD or PD. EASL response was a significant predictor of survival at 3-, 6-, and 12-month Landmarks on uni/multivariate analyses. Conclusion: Response to radioembolization in patients with solitary HCC can prognosticate improved survival. EASL necrosis criteria outperformed RECIST 1.1 size criteria in predicting survival. The therapeutic objective of radioembolization should be radiologic response and not solely to prevent progression. (Hepatology 2018;67:873-883)