Radiographic Parameters in Predicting Outcome of Patients with Hepatocellular Carcinoma Treated with Yttrium-90 Microsphere Radioembolization

Background. In patients with hepatocellular carcinoma, selection criteria for transarterial hepatic selective internal radiotherapy are imprecise. Additionally, radiographic parameters to predict outcome of transarterial hepatic selective internal radiotherapy have not been fully characterized. Patients and methods. Computed tomography (CT) scans of 23 patients with unresectable primary hepatocellular carcinoma before and after transarterial hepatic selective internal radiotherapy with yttrium-90 microspheres were retrospectively reviewed. Selected radiographic parameters were evaluated and correlated with progression-free survival and overall survival. Response to treatment was assessed with Response RECIST 1.1 and Morphology, Attenuation, Size, and Structure (MASS) criteria. Results. On the post-SIRT CT, 68% of tumors demonstrated decreased size (median decrease of 0.8 cm, P = 0.3); 64% had decreased attenuation (median decrease 5.7 HU, P = 0.06), and 48% demonstrated increased tumor necrosis (P < 0.001). RECIST-defined partial response was seen in 10% patients, stable disease in 80%, and 10% had disease progression. Median progression-free survival was 3.9 months (range, 3.3 to 7.3), and median overall survival was 11.2 months (7.1 to 31.1). Pretreatment lower hepatopulmonary shunt fraction, central hypervascularity, and well-defined tumor margins were associated with improved progression-free survival. Conclusion. In patients with unresectable hepatocellular carcinoma, pretreatment CT parameters may predict favorable response to SIRT and improve patient selection.