Caren van Roekel

120 Chapter 4 ABSTRACT Purpose To evaluate the safety and feasibility of one-day treatment, including the simulation procedure for assessment of intra- and extrahepatic distribution of the microspheres, with holmium-166 ( 166 Ho)-radioembolization. Materials and methods This was a secondary analysis of patients included in the four prospective studies (HEPAR I, II, PLuS and SIM studies) on 166 Ho-radioembolization. Technical success rate of the one-day treatment protocol was measured, which was defined as the number of patients who completed one-day treatment. Total in-room time, duration of the scout procedure, time to imaging and duration of the treatment procedure were recorded. Reasons for discontinuation or adjustment of treatment were identified. Adverse events (CTCAE v5.0) that occurred during the treatment day were recorded. Results 105 of 120 scheduled patients completed one-day treatment with 166 Ho- radioembolization(success rate 88%). After the simulation procedure, treatment was cancelled in fifteen patients because of extrahepatic deposition (n=8), suboptimal tumor targeting (n=1), unanticipated vascular anatomy (n=5) and dissection (n=1). In another 14 patients, the treatment plan was adjusted. The median total procedure time (i.e. simulation, imaging and treatment) was 6:39 hours (range 3:58-9:17 hours). Back pain was a major same-day treatment related complaint (n=28). Conclusion 166 Ho-radioembolization as a one-day treatment procedure is feasible in the majority of selected patients, although treatment was adjusted in 12% of patients and cancelled in 12% of patients. This approach may be beneficial for a select patient population, i.e. patients needing a radiation segmentectomy. Keywords Radioembolization, holmium-166, hepatic tumors