Abstract #1165887: Metastatic Anterior Mediastinal Paraganglioma Treated with Lu-177-DOTATATE

Abstract

Peptide receptor radionuclide therapy (PRRT) may be an option for the treatment of patients with surgically inoperable paragangliomas. We present a case of metastatic anterior mediastinal paraganglioma treated with Lu-177-DOTATATE. A 55 year old male with unexplained tachycardia was evaluated in the emergency department for severe hypotension, chest tightness and dizziness. An ECG showed inferior lead ST elevations prompting emergent cardiac catheterization. Coronary angiography revealed complete obstruction of the mid-right coronary artery and a hypervascular extracardiac mass perfused from the right and left coronaries. Subsequent aortic CT and cardiac MRI demonstrated a 7.3 cm hypervascular epicardial mass and an indeterminate hepatic lesion. Further evaluation with Gallium-68 DOTATATE PET-CT revealed an intensely avid anterior mediastinal mass and slightly avid liver lesion. A 24 hour urine study revealed normal metanephrines and epinephrine but elevated norepinephrine 159mcg/24hr [15-80] and an unmeasurably high dopamine. He was started on alpha and beta-adrenergic blockade, which improved his palpitations and tachycardia. Liver biopsy confirmed the diagnosis of metastatic paraganglioma. Cardiothoracic surgery recommended neoadjuvant chemotherapy followed by debulking surgery. Following 3 cycles of CyADIC (cyclophosphamide, doxorubicin, dacarbazine), PET-CT imaging demonstrated increasing size of liver metastases and tumor burden not amenable to surgery. Furthermore, he experienced chemotherapy side effects including thrush, grade 2 fatigue, grade 2 mucositis and dose delay from grade 3 neutropenia. A multi-disciplinary tumor board discussed palliative treatment options to include PRRT with Lu-177-DOTATATE. His first administration of Lu-177-DOTATATE was 100 mCi and performed in the medical ICU due to concern of precipitating a catecholamine crisis. The patient tolerated the infusion without complications. After the first dose of Lu-177-DOTATATE, his neuroendocrine neoplasms test (NETest) score decreased from 53 to 27, reflecting disease stabilization. The patient later received a second dose of 100 mCi Lu-177-DOTATATE followed by two doses of 200 mCi approximately 8 weeks apart. Serial post-treatment scans did not demonstrate new sites of metastatic disease while undergoing PRRT. Two months following his final dose of Lu-177-DOTATATE, the patient expired from liver failure related to his extensive hepatic metastases. Our patient with inoperable metastatic anterior mediastinal paraganglioma achieved disease stabilization with Lu-177-DOTATATE with minimal toxicity. Lu-177-DOTATATE should be considered as a palliative treatment option for inoperable metastatic paraganglioma.