Radiotheranostics of neuroendocrine neoplasms: <i>quo vadis</i>

Neuroendocrine neoplasms are grouped based on their neuroendocrine origin and represented by a heterogeneous tumor cluster with various malignancy potentials and types of biological behavior. These tumors can localize anywhere, but most commonly within the gastrointestinal tract. The ability of tumor cells to express specific receptors and particulars of their metabolism make it possible to successfully use molecular visualization (single-photon emission computed tomography / positron emission tomography) and radiotargeted therapy for diagnosis and treatment of patients with neuroendocrine tumors. In clinical practice, somatostatin receptor (receptors type 2) radiotheranostics has been used most widely. Improvement of diagnostic and therapeutic characteristics of new radioligands, discovery of new receptor and metabolic targets, widening of the medical isotope spectrum and development of new theranostic pairs open wide horizons for radiotheranostics as an integral field in modern biomedicine. The paper summarizes the worldwide experience, highlights the state-of-the-art and future development of radiotheranostics of neuroendocrine tumors.