Peptide receptor radionuclide therapy for neuroendocrine tumours

Background Neuroendocrine tumours (NETs) are a heterogeneous group of tumours that arise in different tissues and organs and have an endocrine and neurological interface that differentiates them into a stand-alone entity. One of their interesting and unique criteria is the overexpression of somatostatin receptors (SSRs) on their cell membrane, which has allowed for specific diagnostic imaging techniques and targeted therapy like peptide receptor radionuclide therapy (PRRT). Objective The aim of this study is to provide a literature review summarizing the latest available studies concerning the use of PRRT in treatment of neuroendocrine tumours including patient selection, the choice of PRPP, efficacy, side effects, and complications. Methods A comprehensive search strategy was used based on SCOPUS and PubMed databases. We considered all studies published in English evaluating the use of PRRT (Lu-177-Dotatate and Y-90-Dotatate) in treatment of NETs and its effectiveness and side effects and complications. Results PRRT was found to be effective as monotherapy or in combination with other therapies. (90)Yttrium may be more appropriate for larger tumour lesions, while (177)Lutetium is more appropriately used for smaller ones. A combination therapy with (90)Yttrium and (177)Lutetium has been suggested for variable sized lesions. Mild acute side effects were reported more in (177)Lutetium, while sub-acute and long-term side effects are more with (90)Yttrium. Heamatotoxicity is usually mild and reversible and only < 15% may progress into severe toxicity. Renal toxicity was greatly reduced to < 3% by kidney protective measures. Conclusions PRRT is well-tolerated and effective treatment modality for non-operable and/or metastatic neuroendocrine tumours. Side effects are usually mild and reversible. More work needs to be done regarding standardization of dosing, timing, and patient selection criteria and ways of follow-up to obtain the maximum potential benefit.