8 This increases the probability of blood stasis Nutlin-3a in vitro in the tumor supplying arterial vessel during therapy (=embolizing effect) causes enhanced probability of a backflow of spheres into small collateral arteries to the stomach, the duodenum, or the pancreas.19 Although this phenomenon may be less frequent with Y-90 glass microspheres in general, we avoided it completely by introducing SPECT-CT after application of Tc99-MAA. The additional

cross-sectional imaging of the MAA significantly enhanced the detection of accidental deposition of microspheres and has been reported by our group.20 The value of SPECT-CT after MAA application in our study was in particular highlighted by nine patients who additionally underwent evaluation for Y-90 treatment, but ultimately were excluded (and therefore are not a part of this report) on the basis

of increased pulmonary shunting or noncorrectable gastrointestinal shunting. Because pneumonitis and gastrointestinal ulcerations were negligible, the third and probably most important safety issue in our study was hepatotoxicity by nontarget irradiation of liver tissue. The significance of hepatotoxicity is emphasized by the fact that HCC in Europe is present in >90% of patients with liver cirrhosis. In our cohort more than half of the patients showed a transient selleck screening library bilirubin elevation, corresponding to other reports of patients treated with radioembolization.17, 21 However, elevation of bilirubin, as a surrogate marker for hepatotoxicity, was only moderate and not related to clinically MCE relevant symptoms in the majority of cases. The three patients who developed clinical signs of hepatic decompensation were

all in Child B status with a CTP score >6 prior to initiation of treatment, indicating that patients with detectable liver function impairment (Child B) are at increased risk for radiation-induced liver disease (RILD) and have to be selected very carefully. A future method to improve selection of patients in order to prevent RILD may be SPECT-CT, because it allows quantification of the uptake of spheres into the tumor as a function of its arterial hypervascularity as well as estimation of nontarget irradiation of the normal surrounding cirrhotic liver tissue. Radiological response parameters and in particular TTP are believed to predict survival after locoregional therapy. Moreover, both are important prognostic factors in an individual patient.13 TTP in our sample was 10.0 months (95% CI 6.1-16.4 months) and corresponded well with the TTP reported in another large single-center study, where it was 7.9 months.17 The measurable response rates in our study, however, were slightly lower as in the mentioned study, where an overall response rate of 42% was reported.