Endocrine Abstracts

JOINT2434

Introduction: Pheochromocytomas/paragangliomas (PPGLs) are a group of rare neuroendocrine tumors with an incidence of approximately 0.8 per 100 000 person-years. Due to their rarity, the metabolic dysregulation of patients with PPGL and metabolic evolution after tumor resection are still under investigation.

Aim: To compare the baseline characteristics of patients across catecholamine phenotypes and investigate post-operative changes in the metabolic profile.

Methods: This is a multicenter, retrospective study conducted at four Endocrinology departments of Greek tertiary general hospitals. Comparisons were performed at diagnosis between catecholamine phenotypes (adrenergic versus noradrenergic) and incidentalomas versus non-incidentalomas. Correlations between metabolic and pheochromocytoma-related characteristics (tumor size, PASS) were performed and metabolic profile evolution after adrenalectomy was assessed.

Results: Overall, 83 individuals [58% females, median age 51 years] diagnosed and treated for pheochromocytoma over the past twenty years were included. Pheochromocytomas were found incidentally in the majority of patients (64%), with 74% of the total cases being secreting tumors. Among those, 28% had adrenergic and 46% noradrenergic phenotype, respectively. The majority of patients (69%) had hypertension which was paroxysmal in 37% of cases. Metabolic disorders at baseline were common with a 74% prevalence of diabetes and prediabetes, 65% of dyslipidemia and 20% of obesity. Adrenergic phenotype was predominant in older individuals (P=0.003) and required significantly higher daily doses of phenoxybenzamine (P=0.002). Metabolic and tumor parameters did not differ between catecholamine phenotypes. Patients diagnosed with incidentalomas exhibited a higher prevalence of diabetes in comparison to their non-incidentaloma counterparts (P=0.021) while the lipid profile did not vary. Hypertensive patients had larger tumors (53.7 vs 42.1 mm, P=0.023) with worse PASS (≧4) (P=0.022). Furthermore, univariate correlations demonstrated that greater tumor size was associated with higher number of anti-hypertensive drugs at diagnosis (P=0.044) and increased PASS in histology (P=0.007). Positive correlations between daily phenoxybenzamine dose and BMI (P=0.002) as well as between HbA1c and number of anti-hypertensive drugs (P=0.029) were observed. Seventy- five patients were followed-up after adrenalectomy for a median period of 24 months. Metabolic assessment revealed improved HbA1c, fasting glucose and LDL levels (P<0.02) despite no significant change in post-operative BMI.

Conclusion: This population-based study, spanning two decades, offers valuable insights into the clinical characteristics of PPGLs patients. Metabolic and tumor parameters showed no variation across catecholamine phenotypes. On the other hand, metabolic disorders demonstrated improvement after adrenalectomy while BMI was not a contributing factor in this context as it remained stable.