Nils Rathmann MD, Presenter: Nothing to Disclose

Joachim Schuette MD, Abstract Co-Author: Nothing to Disclose

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

Stefan Oswald Schoenberg MD, PhD, Abstract Co-Author: Institutional research agreement, Siemens AG

Steffen J. Diehl MD, Abstract Co-Author: Nothing to Disclose

Peter Hohenberger, Abstract Co-Author: Nothing to Disclose

To our knowledge no data exists in concern of gastrointestinal stromal tumor (GIST) liver metastases being treated with selective internal radiation therapy (SIRT). Purpose of this study is to evaluate the therapy response and progression free interval (PFI) of GIST liver metastases after SIRT.

From 2008 to 2013 nine patients with GIST liver metastases being progressive under tyrosine kinase inhibitors (TKI) treatment were referred. Five patients had liver metastases only, in another four patients extrahepatic disease was controlled by TKI. Depending on intrahepatic tumor distribution, either one or both liver lobes were treated intraarterially. Contrast enhanced (CE) MRI, CE CT and 18F-FDG PET-CT were used for follow-up. All patients resumed the TKI therapy after SIRT.

16 liver lobes of 9 patients were treated with a mean activity of 1.06GBq per lobe. No radiation induced liver disease (RILD) occurred, however one patient required surgery for persistent stomach ulcer. Three patients had a complete remission (CR), five patients partial response (PR) and one patient stable disease (SD). No patient showed progression after SIRT. Median PFI was 15.89 months (range 4-29). Median survival was 29.78 months (range 10-72).

SIRT offers a safe and effective treatment option in patients with liver metastases from GIST not or no longer responding to TKI treatment. In patients with mutational status known to be insensitive to available tyrosine kinase inhibitors SIRT could be an option for earlier phases of therapy. The results might also contribute to challenging the radiation resistance assumed for GIST.

Our study presents distinct advantages of SIRT in terms of PFI and survival in patients with GIST suffering from progression of liver metastases.

Rathmann, N, Schuette, J, Pink, D, Schoenberg, S, Diehl, S, Hohenberger, P, Retrospective Analysis of Patients Suffering from GIST Liver Metastases Resistant to Tyrosine Kinase Inhibitors being Treated with SIRT.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14009322.html