EYES2024 ESE Young Endocrinologists and Scientists (EYES) 2024 Adrenals and Neuroendocrine Tumors (17 abstracts)
1Department of Nuclear Medicine, LMU Klinik Munich; 2Department of Radiology, LMU Klinik Munich; 3Department of Endocrinology, LMU Klinik Munich
Introduction: Somatostatin receptor (SSTR)-targeted PET/CT is widely used for diagnosing and monitoring pheochromocytoma and paraganglioma (PPGLs). This study aims to evaluate the potential of the novel SSTR-targeted tracer [18F]-SiTATE in diagnosing PPGLs by comparing imaging parameters with tumor marker levels and secretory activity in a small cohort of patients diagnosed with PPGL.
Methods: All patients with histologically confirmed PPGL who presented for [18F]-SiTATE-PET/CT at LMU Klinikum between October 2020 and February 2024, along with hormonal laboratory analysis of both plasma and 24-hour urine samples within up to 100 days, were included. Metabolic tumor volume (MTV) was assessed using a threshold of mean standard uptake value (SUVmean) of 5.0. Total lesion uptake (TLU) was assessed as SUVmean × MTV. Correlation was tested using Spearmans rank correlation test.
Results: Thirty-four out of 39 patients (median age: 55, range: 5-83) were included in this study, with 5 patients with cervical PGL excluded. Twenty-one patients had metastatic disease. There was a moderate correlation between TLU and MTV and urinary dopamine (r = 0.50-0.51, P < 0.05) as well as norepinephrine (r = 0.50-0.54, P < 0.05). TLU and MTV also moderately correlated with serum chromogranin-A levels (r = 0.60, P < 0.01). Additionally, a moderate correlation was found between TLU and MTV with plasma normetanephrine and 3-methoxytyramine (r = 0.52-0.56, P < 0.01).
Conclusion: MTV and TLU measured with [18F]-SiTATE-PET/CT correlate well with serum chromogranin-A and specific catecholamine pathway biomarkers in urine and plasma, reflecting metabolic tumor activity. Despite the limitations of the relatively small cohort, our results suggest that TLU in [18F]-SiTATE-PET/CT could be used as an imaging biomarker for monitoring disease progression and secretory activity in patients with PPGL.