MON-196 A Single-Center Experience of Patients with Metastatic Pheochromocytoma/Paraganglioma Treated with (177)Lu-DOTATATE

The prevalence of metastatic pheochromocytoma/paraganglioma (PPGL) is reported to be 3% to 36% of all the cases. The five-year overall survival rate of such patients ranges from 40 to 77%. The management of metastatic PPGL is challenging taking into account the fact that the optimal strategies for clinical care beyond surgical resection are not guided yet. Peptide receptor radionuclide therapy (PRRT) using somatostatin analogues is effective in other neuroendocrine tumours, can be indicated in patients with positive scans for the respective radiopharmaceuticals. We report preliminary data of the prospective study aimed to assess the safety and efficacy outcomes of 177Lu-DOTATATE for 6 patients with histologically confirmed PPGLs with metastatic progression after the complete PPGL surgery. The mean age of our cohort was 53 years (range 14–73); an equal number of male and female patients was included. Two of them had germline mutations in RET and SDHB genes, respectively. Radiological response utilized RECIST 1.1 criteria; toxicity was graded according to common terminology criteria for adverse events version 4. PPRT scheme varied between three and four cycles. Partial response (PR) was achieved in one and stable disease (SD) in four 4 patients. One patient had treatment refractory with disease progression and dramatic increase of chromogranin A concentration (+268%). Biochemical response (>50% decrease) of chromogranin A was found in 1/6 patients and of catecholamines in 2/6 patients. No hematological or kidney toxicity grade 3–4 was registered. Median overall survival and median progression-free survival rate will be reported after the end of the study. To date, about 250 PPGL patients have been treated with PRRT. PRRT using 177Lu-DOTA-SSAs has shown promise for treatment of PPGLs with improvement of clinical symptoms and/or disease control in the setting of retrospective small case reports or case series. However, more well-designed prospective studies are required to confirm these findings.