Endocrine Abstracts

Purpose: Pheochromocytomas (PCs) and paragangliomas (PGLs) are rare neuroendocrine tumors arising from chromaffin cells of the adrenal medulla and the sympathetic/parasympathetic neural ganglia, respectively. Metastatic PCs/PGLs occur in about 5-26% of cases. Their management and diagnosis still remain a challenge due to their heterogeneity, the absence of guidelines and the few prognostic tools.

Aim: The aim of this study was to describe clinical and genetic characteristics of a series of PCs/PGLs patients in a tertiary center as well as to evaluate their diagnostic and therapeutic approach.

Methods: Clinical data of 50 (30 females) patients (25 with PCs and 25 with PGLs) referred to the University Hospital of Laikon were retrospectively collected and analysed.

Results: Patients’ follow-up ranged from 12 to 93 months (median: 31). The 84% of PCs and 36% of PGLs were functional. Genetic analysis was performed in 50% of the total included patients (n=12/25 patients with PCs and n= 15/25 with PGLs) and was found positive in both blood and tissue analysis in 12 patients (9 with SDHD/B, 2 with RET and 1 with NF-1 mutation). Genetic mutations were twice as common in PGLs (15%) compared with PCs (7%). Median PASS was 5 (min-max:4-7) for PCs and GAPP 5 (min-max:2-11) for PGLs. Median Ki-67% index levels was 3(min-max:1-18). In 96% of PCs surgery was the treatment of choice compared to 72% of PGLs. Metastatic disease (n=9) or local recurrence (n=5) were found in 14/50 (28%) of patients; 25% of them with PCs and 26% with PGLs. Surgery was more often chosen (2^nd line treatment) for PCs’ recurrence or metastasis (37%) compared to PGLs (16%) in which systemic treatments including chemotherapy (temozolomide), radiopeptides, targeted treatment, radiotherapy or follow-up (watch and wait strategy) were applied. MSI/PDL1 expression was negative in 10 tested samples (all metastatic or progressive) and thus immunotherapy was not considered. Survival rate was 98% during the follow-up. Median progression free survival was 36 months for patients with metastatic disease, and median overall survival 96 and 48 months in patients with PCs and PGLs respectively.

Conclusion: In our series, 44.4% of patients with PCs and PGLs were diagnosed with genetic mutations confirmed in both bood and tissue analysis whereas the frequency of patients with PGLs diagnosed with pathological mutations was double compared to patients with PCs. The 28% of our cases presented local recurrence or distant metastases; however MSI/PDL1 analysis was negative and thus immunotherapy was not applicable.