Caren van Roekel

138 Chapter 5 treatment CEA level (19, 24, 25). These factors could possibly be used in patient selection as well. The aim of this study was to assess the impact of baseline characteristics on changes in intra- and extrahepatic mCRC disease from baseline to three months after radioembolization, across all currently available radioembolization treatment modalities. METHODS Patient selection and study design A total of 129 chemorefractory, unresectable mCRC patients were treated with radioembolization at our institution between August 2009 and January 2017, predominantly as part of the HEPAR-2 (Holmium Embolization Particles for Arterial Radiotherapy II) (26), or RADAR trial (RADioembolization: Angiogenic factors and Response) (22). The studies were conducted in accordance with the institutions’ Medical Ethical Committee and informed consent was obtained from the patients treated in the HEPAR-2 and RADAR studies before inclusion. For the other patients that were treated in routine clinical practice and also included in the current retrospective analysis, the need for informed consent was waived. Inclusion criteria for all patients regarding the presence of extrahepatic metastases or the primary tumor were similar: liver-dominant disease with a maximum of five lung nodules <1 cm and lymph nodes <2 cm. The presence of the primary tumor was not a contra-indication to treatment. Patients were included for response analysis in case CT and/or MRI scans were available at baseline and at (around) three-months follow-up; all patients were included for survival analysis. Patients were treated with 166 Ho-microspheres (n=24)(all as part of the HEPAR 2 study), glass 90 Y-microspheres (n=20), or resin 90 Y-microspheres (n=46). Imaging was performed three months after treatment (i.e. whole-liver or lobar treatment in one session). In case of sequential lobar treatment, imaging was performed three months after the last lobar treatment. The electronic medical records were reviewed to obtain patient characteristics. The following established independent prognostic factors in patients with mCRC were compared: age, number of previous chemotherapy lines, type of microspheres, presence of extrahepatic disease at baseline, primary tumor in