Integrated use of90Y-labeled microspheres and immune checkpoint inhibitors in hepatic tumors: current status and future directions

Introduction: Transarterial radioembolization (TARE) with yttrium-90 (90Y)-labeled microspheres and immune check-point inhibitors (ICIs) have been successfully applied for the management of advanced hepatocellular carcinoma (HCC) and hepatic metastases. The potential synergism of 90Y-microspheres and ICIs in integrated therapeutic regimens represents a topic of great interest. Areas covered: The main characteristics of resin and glass 90Y-microspheres are covered, as well as the basic principles of TARE. Furthermore, the existing literature on the integrated use of 90Y-microspheres with ICIs in HCC and hepatic metastases are discussed. Expert opinion: 90Y-microspheres and ICIs have been employed in integrated approaches in patients with advanced HCC, liver metastases from uveal melanoma (UMLM) and colorectal cancer (CRCLM). In all cases, toxicity profile results were tolerable. A favorable impact on survival was registered for HCC and UMLM, but 90Y-microspheres did not help sensitize microsatellite-stable CRCLM to immunotherapy. Particular caution should be paid in UMLM patients undergoing combination therapy with ipilimumab plus nivolumab. In this regard, the potential usefulness of provisional dosimetry to estimate the radiation burden delivered to the normal hepatic parenchyma has still to be fully addressed.