68Gallium- and 90Yttrium-/ 177Lutetium: "theranostic twins" for diagnosis and treatment of NETs

Abstract

Abundant expression of somatostatin receptors (SSTR) is frequently identified in differentiated neuroendocrine tumors and may serve as potential target for diagnostic imaging and treatment. This article discusses the "theranostic approach" of SSTR-targeting compounds including an overview of its role for diagnosis, staging and restaging, discussing its way to being established in clinical routine, and giving an outlook about further potentially relevant developments.

Fig. 1

69-year-old male suffering from Ileum NET (primary tumor) with paraaortal thoracic lymph node metastases. Left pretherapeutic ⁶⁸Ga-DOTATOC PET/CT (anterior view, trans-axial view) showing primary tumor (ileum) and paraaortal mediastinal lymph node metastases. Right posttherapeutic fused SPECT/CT after administering 7.4 GBq ¹⁷⁷Lu-DOTATATE showing prominent uptake in the primary tumor and paraaortal thoracic lymph node metastases

Fig. 2

56-year-old male suffering from unresectable pancreatic NET (primary tumor) with liver metastases and retroperitoneal lymph node metastases. Left pre-therapeutic ⁶⁸Ga-DOTATOC PET/CT (anterior view, trans-axial view) showing liver metastases and retroperitoneal lymph node metastases. Right post-therapeutic ⁶⁸Ga-DOTATOC PET/CT (anterior view, trans-axial view) after administering 22.3 GBq ¹⁷⁷Lu-DOTATOC over the course of 3 treatment cycles showing reduced uptake in the metabolically regressive liver and retroperitoneal lymph node metastases (staging 10 weeks after last treatment cycle)