Caren van Roekel

35 Radioembolization In a study of 122 patients with primary and metastatic hepatic tumors, Abdelmaksoud et al. investigated the development of new hepatoenteric collaterals. These patients underwent a preparatory angiography before treatment with radioembolization, during which hepaticoenteric collaterals were embolized. At the time of radioembolization, new collaterals had developed in 42 patients (34.4%), requiring adjunctive embolization. The mean time interval between the preparatory and treatment angiography in this subgroup was 14.7 days (range 1-72) (40). In 2007, one of the official recommendations of the radioembolization brachytherapy oncology consortium was that ‘all extrahepatic vessels originating from the hepatic arteries that supply the gastrointestinal tract should, under most circumstances, be embolized to exclude extrahepatic deposition of the 90 Y microspheres’ (65). However, the rapid development of new hepaticoenteric collaterals opposes this so-called skeletonization and brings it benefit into question. In a review, Borggreve et al. looked into the evidence supporting prophylactic embolization. They found that refraining from embolization of the GDA, right gastric artery (RGA) and the cystic artery (CA) is justified when the catheter tip can be placed distal to the origin of these arteries (66). It is recommended to use a more distal injection position, already during the scout procedure. 5.2. Medication During treatment, it is common practice to monitor vital signs (blood pressure, pulse and saturation). Recently, a large study was published on adjuvant medications that improve survival after locoregional therapy, such as radioembolization. The medications were taken at the time of embolization. Beta-blockers and aspirin were associated with improved survival in HCC patients. These medications were not associated with improved survival when taken by patients with neuroendocrine tumors or colorectal cancer liver metastases (67). The authors provided the following hypotheses for the mechanisms behind this survival benefit: (1) aspirin inhibits hypoxia-induced angiogenesis, which might prevent radioembolization-induced ischemia from promoting angiogenesis and growth of the residual viable tumor. It also inhibits glycolysis, which may make tumor cells less likely to survive radioembolization- induced ischemia. Furthermore, aspirin is a COX inhibitor and COX-2 inhibition promotes an antitumor immune response. (2) Beta-blockers decrease blood flow in the portal vein, which is associated with improved response after 2