['Conventional transarterial chemoembolization (cTACE) is used to treat patients with hepatocellular carcinoma (HCC). Radioembolization is a minimally invasive procedure that involves implantation of radioactive micron-sized particles loaded with yttrium-90 (Y90) inside the blood vessels that supply a tumor. We performed a randomized, phase 2 study to compare the effects of cTACE and Y90 radioembolization in patients with HCC.', 'From October 2009 through October 2015, we reviewed patients with HCC of all Barcelona Clinic Liver Cancer (BCLC) stages for eligibility. Of these, 179 patients with BCLC stages A or B met our enrollment criteria and were candidates for cTACE or Y90 therapy. Patients were assigned randomly to groups that received Y90 therapy (n\xa0= 24; 50% Child-Pugh A) or cTACE (n\xa0= 21; 71% Child-Pugh A). The primary outcome was time to progression (TTP), evaluated by intention-to-treat analysis. Secondary outcomes included safety, rate of response (based on tumor size and necrosis criteria), and Kaplan-Meier survival time. We performed inverse probability of censoring weighting and competing risk analyses.', 'Patients in the Y90 radioembolization group had significant longer median TTP (>26 mo) than patients in the cTACE group (6.8 mo; P\xa0= .0012) (hazard ratio, 0.122; 95% confidence interval [CI], 0.027-0.557; P\xa0= .007). This was confirmed by competing risk and inverse probability of censoring weighting analyses accounting for transplantation or death. A significantly greater proportion of patients in the cTACE group developed diarrhea (21%) than in the Y90 group (0%; P\xa0= .031) or hypoalbuminemia (58% in the cTACE group vs 4% in the Y90 group; P < .001). Similar proportions of patients in each group had a response to therapy, marked by necrosis (74% in the cTACE group vs 87% in the Y90 group) (P\xa0= .433). The median survival time, censored to liver transplantation, was 17.7 months for the cTACE group (95% CI, 8.3-not calculable) vs 18.6 months for the Y90 group (95% CI, 7.4-32.5) (P\xa0= .99).'] Does y90 Radioembolization Significantly prolong Time to Progression Compared With Chemoembolization in Patients With Hepatocellular Carcinoma?