Peptide receptor radionuclide therapy in neuroendocrine neoplasms and related tumors: from fundamentals to personalization and the newer experimental approaches

Abstract

Introduction Peptide Receptor Radionuclide Therapy (PRRT) is a type of molecular-targeted endo-radionuclide therapy in which unsealed radiolabelled somatostatin analogues are specifically directed toward somatostatin receptors (SSTR) over-expressed in Neuroendocrine Neoplasms (NEN) and related malignancies. This modality has witnessed a benchmark growth over last decade and symbolizes remarkable development in precision oncology. The tumor selectivity and excellent tolerability with minimal side effects make this one of the preferred therapeutic options in metastatic progressive NENs.Areas covered This review deliberates upon fundamentals of PRRT, its indications and employment as a therapeutic modality for precision oncology. A few special scenarios based on our experiences and expertise have also been mentioned. A short discussion on current advancements worldwide and future directions has also been included.Expert opinion SSTR-based PET and PRRT are now an established theranostic approach in management of NENs. Its spectrum has expanded in the form of Neo-Adjuvant-PRRT, Sandwich Chemo-PRRT, Duo-PRRT, Salvage-PRRT, and Intra-arterial-PRRT. Its application to other SSTR-expressing tumors includes metastatic/inoperable medullary thyroid cancer, neural crest malignancies like pheochromocytomas-paragangliomas (PPGLs), Merkel cell carcinoma, radioiodine-refractory thyroid cancer, and meningiomas. Though substantial prospective evidence is still lacking, a multidisciplinary team should adopt PRRT in appropriate indications by using dual tracer PET imaging as a gatekeeper.