Efficacy of Peptide Receptor Radionuclide Therapy (PRRT) for Functional Metastatic Paraganglioma and Phaeochromocytoma.

Efficacy of Peptide Receptor Radionuclide Therapy (PRRT) for Functional Metastatic Paraganglioma and Phaeochromocytoma.

J Clin Endocrinol Metab. 2017 Jun 09;:

Authors: Kong G, Grozinsky-Glasberg S, Hofman MS, Callahan J, Meirovitz A, Maimon O, Pattison DA, Gross DJ, Hicks RJ

Abstract
Purpose: Treatment options for unresectable Paraganglioma (PGL)/Phaeochromocytoma (PCC), especially with uncontrolled secondary hypertension (HTN) are limited. Preliminary studies with PRRT suggest efficacy but data on HTN control and survival are lacking. We assessed PRRT outcomes in such patients from 2 referral centres.
Methods: 20 consecutive patients (M:F=13:7; 21-77y.o.) with high somatostatin receptor (SSTR) expression treated with 177Lu-DOTA-octreotate, 9 with radiosensitising chemotherapy, were retrospectively reviewed. Median cumulative activity was 22 GBq (1-4 cycles, median 4). Fourteen patients were treated for uncontrolled HTN, and 6 for progressive or symptomatic metastatic disease or local recurrence.
Results: Three months post-PRRT, 8/14 patients treated for HTN required reduced medication doses, 5 patients had no change in anti-HTN doses, and 1 patient was lost to follow-up. 86% had serum chromogranin-A reduction. For the entire cohort, 36% had disease regression (29% partial, 7% minor response) on CT, with stable findings in 50%. Three other patients had bony disease evaluable only on SSTR imaging (2 partial response, 1 stable). Median progression-free survival was 39 months, median overall survival was not reached (5 deaths, median follow-up 28 months). Four patients had Grade 3 lymphopenia, 2 Grade 3 thrombocytopenia. Renal impairment in 2 patients was attributed to underlying disease processes.
Conclusions: Our results indicate that PRRT achieves worthwhile clinical and biochemical responses with low toxicity as well as controlling secondary HTN in most patients with PCC/PGL and encouraging survival. PRRT also has potential logistic and radiation-safety advantages over conventional 131I-MIBG therapy and warrants prospective evaluation in this clinically heterogeneous disease.

PMID: 28605448 [PubMed - as supplied by publisher]

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