A re-evaluation of dopamine excretion in phaeochromocytoma

In a re-evaluation of the use of dopamine as a prognostic factor in phaeochromocytoma, a series of 34 patients was imaged with iodine-131-meta-iodobenzylguanidine, a radiopharmaceutical specifically localized in chromaffin tumours. Fourteen patients were found to have malignant disease. Increased dopamine excretion was found in 9 (64%) of these patients including all four with primary intra-adrenal tumours, and this was associated with a poor prognosis. Of the five patients in the malignant group with normal dopamine excretion on referral, the disease extent was minimal and in four the primary tumour had been resected. Twenty patients appeared to have benign phaeochromocytoma from the imaging results. Of these, 16 were intra-adrenal and four were extra-adrenal. In 19 the dopamine excretion was within the control range but in one it was marginally increased. From these observations it would seem that dopamine excretion may be a useful prognostic factor when combined with imaging to determine the extent of the disease.