Prevention Medicine in Bilateral Phaeochromocytoma

Background: Adrenalectomy is standard of care for phaeochromocytomas, but for bilateral phaeochromocytoma, the recommendations are inconsistent. However, large studies systematically investigating long-term outcomes for total adrenalectomies compared to those for patients with adrenal-sparing operations are lacking.   Methods: A multi-center consortium-based registry was established to study clinical, genetic and surgical data in 623 patients with bilateral phaeochromocytomas. Findings: Of 623 patients, median age at diagnosis was 30 (range 3-79) years and 48% were female. Synchronous bilateral phaeochromocytomas were diagnosed in 396 patients and metachronousphaeochromocytomas in 227 (36%); interval to second operations were up to 40 (median 6) years. In 96% of tested patients germline mutations were detected in the genes RET (56%), VHL (34%), and others (10%). Of 849 operations, 385 (45%) surgeries in 326 patients were planned as adrenal-sparing which was successful in 251. 372 patients became steroid-dependent. Follow-up was up to 53 (median 11) years. Adrenal crises developed in 67 patients (18%) during follow-up, and 49 (13%) had manifestations of iatrogenic Cushing syndrome. Of the steroid-independent patients, 34 (14%) had developed another phaeochromocytoma within the remnant adrenal after up to 27, median 8 years, all treated with removal of the new phaeochromocytoma. Overall survival was mainly influenced by non-phaeochromocytoma comorbidities, whereas only 1% died of metastatic phaeochromocytoma. Cortical-sparing operations did not affect survival.   Interpretation: Cortical-sparing operations avert lifelong steroid-dependency without affecting survival. Preoperative genetic testing is recommended even in unilateral phaeochromocytoma presentations to identify patients at heritable risk, to guide surgical approach, and inform for gene-specific extra-adrenal morbidities.   Funding Statement: Supported in part by the grant AZV 16-32665A to Sarka Dvorakova and Petr Vlcek, and the Blank Foundation to Charis Eng. Declaration of Interests: None of the authors have relevant conflicts of interest. Ethics Approval Statement: The institutional review boards for human subjects’ protection or ethical committees of all participating centers approved this study. Patients provided written informed consent according to the protocols of respective institutional review boards. In The Netherlands data were collected anonymously, and no further Institutional Review Board approval is required.