Italian Multicenter Experience With Radioreceptor-assisted Therapy (PRRT) in Pheochromocytomas and Paragangliomas: a Retrospective Analysis

Pheochromocytomas (PHEO) and paragangliomas (PGL), collectively referred to as PPGL, are rare neuroendocrine tumors, sometimes secreting catecholamines, with variable clinical presentations and a risk of advanced/metastatic disease. In patients not eligible for curative treatment or with progressive disease, multimodal strategies may be used, including systemic and radiometabolic therapies, although shared therapeutic algorithms are difficult to define. In particular, in PPGL with somatostatin receptor expression documented by functional imaging, PRRT (Peptide Receptor Radionuclide Therapy) represents a therapeutic option used in an experimental/off-label setting, within authorized clinical protocols or clinical trials, as reported in the literature. Between 2000 and 2024, several centers in Italy treated PPGL patients with PRRT using different regimens (radionuclide, number of cycles, and timing), depending on experimental protocols, technological availability, and clinical characteristics. This heterogeneity, combined with the rarity of the disease, highlights the relevance of a structured national collection of real-world data to describe the efficacy and safety of PRRT in this setting. This is a retrospective, multicenter, non-profit observational pharmacological study including adult patients (≥18 years) with documented PPGL and advanced/unresectable or metastatic disease who received at least one cycle of PRRT within the study period. Patients must have available essential data to document treatment exposure and outcomes, including at least one post-treatment evaluation for disease control and minimum data for progression-free survival assessment.

PRRT exposure includes treatments administered within completed clinical trials or authorized protocols at participating centers. Data collected will include type of radionuclide(s), number of planned and administered cycles, treatment intervals, and reasons for treatment modifications or discontinuation, where available.