Peptide Receptor Radiotherapy: Current Approaches and Future Directions.

OPINION STATEMENT: Neuroendocrine neoplasia (NEN) represents a heterogenous group of tumours. Guidelines regarding treatment choice and sequencing remain complex given varied primary sites, hormone-secretory status, tumour grade, disease heterogeneity, and paucity of rigorous comparative trials due to rarity of this condition. However, there is increasing evidence that peptide receptor radionuclide therapy (PRRT) is an effective treatment, especially for grade 1 and 2 NEN. Primary indications for treatment include oncologic control in patients with progressive disease and symptomatic control in the context of hormone-secretory syndromes or tumour-related pain. However, strategies are needed to further optimize efficacy and outcomes, and to expand treatment indications. Important considerations could include personalized PRRT regimens based on better characterization of the disease in an individual patient. Future directions should also focus on strategies to further enhance the efficacy of PRRT including combination treatments with other systemic therapies, such as radiosensitising chemotherapy, DNA repair-modifying agents and immunotherapy. Further evolution of therapeutic radiopharmaceuticals also offers promise.