Effects of slow-release octreotide in patients with malignant or recurrent pheochromocytoma

Abstract

To investigate the clinical and hormonal effects of a slow-release formulation of the somatostatin analogue, octreotide, in patients with malignant or recurrent pheochromocytoma. In a prospective study, 10 patients underwent 111Indium labelled octreotide scintigraphy and then received three monthly intramuscular 20 mg octreotide injections. Patients were evaluated before the first injection and 30 days after the third injection (D84). The assessed parameters were: symptoms, blood pressure (BP), plasma noradrenaline (NA) concentrations, blood glycosylated hemoglobin (HbA1c), insulinemia, and the levels of two putative markers of tumor burden, urinary metanephrine/creatinine (MN/Cr) and plasma chromogranine A (CGA) concentration. There were no statistically or clinically significant variations in BP levels, MN/Cr excretion ratio, plasma CGA, plasma NA and, or symptoms. Long-acting octreotide was well tolerated but a significant increase in HbA1c was observed (p=0.03). Patients with (n=6) or without (n=4) 111Indium octreotide uptake did not differ in urinary metanephrine excretion, plasma NA, HbA1c, plasma CGA, symptom evolution, and BP,. Patients showing tracer uptake had a larger reduction in plasma insulin that those without (-1.0 mUI/L vs +2.3 mUI/L; p=0.03). Our data suggest that slow-release octreotide is not useful for the long term treatment of patients with malignant or recurrent pheochromocytoma. (See Table)