Reply:

Abstract

We thank Professor Strunk for his interest in our article and appreciate the comments. It is our pleasure to reply to each query. In this 108-patient cohort, radioembolization was always performed either at the lobar or segmental hepatic artery level. Our group has always advocated against the use of whole-liver 90Y treatment, particularly in the patient with cirrhosis who has hepatocellular carcinoma. Although table 1 states that most patients had <50% tumor burden, most of these tumors were large and involved many segments. Hence, it was our standard to inject at the lobar hepatic artery level. When smaller tumors were encountered, a segmental injection was performed in order to spare liver parenchyma from unnecessary radiation. We have never injected 90Y at the proper or common hepatic artery level and do not advocate this approach. The microsphere device used in the study was glass-based. It is well-known that this device delivers a small volume of microspheres with very high specific activity. Hence, this represents an arterial microembolization rather than a macroembolization procedure. As a result, we are always able to inject the prescribed dose; embolization and flow stasis are not factors using this technique. This angiographic concept has been previously described by our group.1 Professor Strunk may be referring to resin microspheres for the treatment of hepatocellular carcinoma. The resin-based device has different radioembolic properties, and therefore flow stasis is more of a factor during the injection process.2 The differences between glass and resin devices are thoroughly summarized by Murthy et al.3 With respect to the errors in the manuscript, we apologize for the oversight. Indeed, for table 1, it should state “71” rather than “1” for the number of patients. In table 2, it should also state “<50” rather than “>50” in the section on tumor burden. Laura Kulik M.D.*, Riad Salem M.D., M.B.A.*, * Northwestern University, Chicago, IL.