Italian Multicenter Experience With Radioreceptor-assisted Therapy (PRRT)

Inclusion Criteria: * Documented diagnosis of pheochromocytoma or paraganglioma (PPGL) (sporadic or hereditary forms) with unresectable or metastatic disease. * Treatment with peptide receptor radionuclide therapy (PRRT) administered with ⁷⁷Lu and/or ⁹⁰Y (including combination regimens), with t0 (first PRRT administration) between January 1, 2000 and February 28, 2024. * Availability of essential data required by the protocol to document exposure (PRRT) and outcomes, including: PRRT start date (t0) and treatment details (radioisotope(s), number of cycles and/or cycles actually administered, intervals when available), At least one post-treatment evaluation suitable for determining disease control rate (DCR) (morphological imaging by CT/MRI ± functional imaging by PET/CT, and available clinical data), Follow-up information suitable for determining progression-free survival (PFS) within the predefined time window. * Availability of follow-up up to 12 months from end of treatment (EoT), or documentation of progression and/or death occurring within 12 months. * Required data and source documents are available at the enrolling center or obtainable from other Italian centers (e.g., PRRT-administering center or centers performing imaging/evaluations) through formal data transfer agreements (e.g., DTA) in compliance with applicable regulations. * Privacy/consent requirements (general framework): For living and contactable patients, consent for personal data processing will be managed according to the requirements/assessment of the Ethics Committee. For deceased or non-contactable patients after reasonable documented efforts, inclusion may occur without consent, as it falls under situations of "impossibility to inform the subjects," in accordance with applicable regulations (Article 110 of the Italian Privacy Code and subsequent amendments), subject to Ethics Committee evaluation/opinion and implementation of appropriate safeguards. Exclusion Criteria: * Patients who did not receive at least one cycle of peptide receptor radionuclide therapy (PRRT).