Wieland H. Sommer MD, Presenter: Nothing to Disclose

Felix Ceelen, Abstract Co-Author: Nothing to Disclose

Marco Armbruster, Abstract Co-Author: Nothing to Disclose

Philipp Paprottka, Abstract Co-Author: Nothing to Disclose

Christoph Auernhammer MD, PhD, Abstract Co-Author: Nothing to Disclose

Carsten Rist MD, Abstract Co-Author: Nothing to Disclose

Maximilian F. Reiser MD, Abstract Co-Author: Nothing to Disclose

Daniel Theisen MD, Abstract Co-Author: Nothing to Disclose

Radioembolization of the liver with 90-Yttrium microspheres is used in patients with unresectable metastases. Some patients show very long progression-free survival after this treatment. The aim of this study was to define the role of MRI in the pretherapeutic prediction of treatment response.

In 45 patients with proven hepatic metastases of neuroendocrine tumors (NET) MRI examinations were performed at baseline in all patients, consisting of standard T1w and T2w sequences,as well as arterial, portal-venous, late-venous and hepatobiliary phase post-contrast sequences (3T MRI scanner, Verio Siemens Medical Solutions, Erlangen, Germany, Gd-EOB-DTPA; Primovist®, BAYER Healthcare, Leverkusen, Germany; 0.025mmol/kgBW, injection rate 2ml/sec). Furthermore, PET-CT examinations (with somatostatin-specific tracer 68Ga-DOTATATE) were performed at baseline. The following imaging predicors were defined: patient age and gender, proliferation marker Ki-67, tumorload in the liver (%), vascularisation of metastases, tumor necrosis, hemorrhage and fluid-fluid levels. In addition to that the status of somatostatin II receptor was defined by analysing mean and maximum SUV in PET-CT. As primary end point we defined the progression free survival (PFS) using RECIST criteria in MRI follow-up examinations (time interval: 3 months). The effects of the predictors on the progression-free.survival have been analyzed by using Kaplan-Meier statistics. The mean follow-up time was 445 ±411 days.

The mean PFS was 699 days (95% CI 326-964). Hypovascular metastases showed significant earlier progress (255 vs. 727 days; p<0.01). A proliferation marker <2% (G1) was siginificantly associated with a longer PFS than a proliferation marker between 2-20% (G2) or >20% (G3) (p<0.001). Patient age, gender, tumor load in the liver, tumor necrosis, hemorrhage as well as radioreceptor status pre-SIRT did not show any impact on PFS (p>0.05).

Radioembolization in neuroendocrine tumors turns out to be most efficient in hypervascular tumors with low proliferation index. Tumor-load as well as radioreceptor status don’t have influence on the progression free survival in contrast to other therapeutic options in NETs.

Pretherapeutical MRI parameters may serve as valuable tool for treatment selection and as a predictor for long progression-free survival after radioembolization of neuroendocrine hepatic metastases.

Sommer, W, Ceelen, F, Armbruster, M, Paprottka, P, Auernhammer, C, Rist, C, Reiser, M, Theisen, D, Predictive Values of MRI Parameters for the Progression-free Survival after Radioembolization in Patients with Metastases of Neuroendocrine Tumors.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12043537.html