Local treatment of liver metastases by administration of Lu-octreotate via isolated hepatic perfusion - A preclinical simulation of a novel treatment strategy.

Introduction: Systemic Lu-octreotate treatment for metastatic neuroendocrine tumours is restricted by organs at risk. By administering Lu-octreotate during isolated hepatic perfusion (IHP), the uptake in organs at risk might be strongly reduced. The aim of this study was to investigate the feasibility to use the combination of IHP and radionuclide therapy.

Methods: To simulate IHP, the liver of a pig was prepared for ex vivo perfusion. Blood containing 490 MBq Lu-octreotate was circulated through the liver for 60 min, after which the liver was rinsed. After IHP, the liver was examined by SPECT/CT. Lastly, an intraoperative gamma detector (IGD) was used to determine Lu activity concentration in the liver and results were compared with the activity concentration in corresponding liver biopsies.

Results: Detector measurements over the liver during the IHP showed a fast increase with a maximum after approximately 10-15 min. After IHP, about 75% of the Lu in the liver could be washed out. The SPECT/CT images revealed a relatively inhomogeneous distribution. Nevertheless, the IGD values of Lu activity concentration showed acceptable agreement with the biopsy values.

Conclusions: Our results in pig show that it could be feasible to treat patients with liver metastases from NETs with Lu-octreotate via IHP . However, an inhomogeneous distribution of Lu-octreotate in normal liver tissue is expected, and in order to determine the activity concentration with satisfactory accuracy using an IGD, measurements need to be performed at several positions over the liver.