At present there is no clinical guideline or standardised protocol for the treatment of metastatic or invasive phaeochromocytoma and
paraganglioma (collectively known as PPGL) due to the rarity of the disease and the lack of prospective studies or extended national databases. Prognosis is mainly determined by
genetic predisposition, tumour burden, rate of
disease progression, and location of
metastases. For patients with progressive or symptomatic disease that is not amenable to surgery, there are various
palliative treatment options available. These include localised
therapies including
radiotherapy, radiofrequency, or
cryoablation, as well as liver-directed
therapies for those patients with hepatic
metastases (e.g., transarterial chemoembolisation) and systemic
therapies including
chemotherapy or
molecular targeted therapies. There is currently intense research interest in the value of
radionuclide therapy for neuroendocrine tumours, including phaeochromocytoma and
paraganglioma, with either
iodine-131 (131I)-radiolabelled metaiodobenzylguanidine or very recently
peptide receptor radionuclide therapy (PRRT), and the most important contemporary clinical studies will be highlighted in this review. The studies to date suggest that PRRT may induce major clinical, biochemical, and radiological changes, with
177Lu-DOTATATE being most efficacious and presenting less toxicity than
90Y-DOTATATE. Newer combination
therapies with combined
radioisotopes, or combinations with chemotherapeutic agents, also look promising. Given the favourable efficacy, logistic, and safety profiles, we believe that PRRT will probably become the standard treatment for inoperable metastatic PPGL in the near future, but we await data from definitive randomised controlled trials to understand its role.