Favorable and Durable Response to Pazopanib in Metastatic Refractory Paraganglioma

Metastatic pheochromocytomas and paragangliomas: where are we?

Pheochromocytomas and paragangliomas (PPGLs) can metastasize in approximately 15-20% of cases. This review discusses the available evidence on the biology and treatment of metastatic PPGLs. Chemotherapy is the first-line treatment option for this evolving and symptomatic disease. In patients with high MIBG uptake and positive PETGa-68, radiometabolic treatment may be considered. The efficacy of sunitinib has been shown in observational studies, and pembrolizumab has been evaluated in phase II clinical studies, while other agents investigated in this setting are anti-angiogenic drugs cabozantinib, dovitinib, axitinib and lenvatinib. As these agents' efficacy and safety data, alone or in combination, are scant and based on few treated patients, enrollment in clinical trials is mandatory. Future therapeutic options may be represented by DNA repair system inhibitors (such as olaparib), HIF2 inhibitors and immunotherapy.

Sunitinib Treatment for Advanced Paraganglioma: Case Report of a Novel SDHD Gene Mutation Variant and Systematic Review of the Literature

Background

Paragangliomas (PGLs) are neuroendocrine neoplasms arising from chromaffin cells of sympathetic or parasympathetic paraganglia. Systemic therapies have been used only in metastatic PGLs. Antiangiogenic agents, such as sunitinib, could be a viable therapeutic choice in the subgroup of patients with SDH-positive PGLs. We describe the case of a man with Familial Paraganglioma Syndrome type 1 (FPGL) related to a novel mutation in SDHD gene treated with sunitinib. Furthermore, we performed a systematic review of the literature aimed to address the following question: is sunitinib treatment effective in patients with advanced/progressive/metastatic PGL?

Methods

We performed a data search using MEDLINE, Cochrane Library, and Scopus between April 2019 and September 2020. We included studies reporting data on clinical or biological characteristics, or clinical outcomes of patients with PGLs treated with sunitinib.

Results

The search leaded to the selection of 25 publications. Data from case reports and case series showed that disease control rate (DCR = stable disease + partial response + complete response) was achieved in 34.7% of cases under sunitinib treatment. In 39% of patients DCR was followed by progressive disease (PD) or tumor relapse, 26.1% patients showed PD. Data from clinical trials showed that DCR was 83%, and the median progression free survival was 13.4 months.

Discussion

Data from the present literature review suggested that sunitinib could be a viable therapeutic option in advanced/progressive/metastatic inoperable PGLs. However, further trials on the efficacy of sunitinib in FPGL and sporadic PGL are needed.

Durable Response to Pazopanib in Recurrent Metastatic Carotid Body Paraganglioma

We present the case of a 26-year-old woman living at a high altitude diagnosed initially with nonfamilial and nonsecretory localized carotid body tumor managed with surgery, which developed into a recurrent metastatic tumor treated with cyclophosphamide, vincristine, and dacarbazine. The patient continued to progress and developed a left carotid artery thrombosis and worsening of her systemic symptoms. The patient was re-evaluated, and she decided on no further surgery or systemic therapy. DOTATATE positron emission tomography/computed tomography showed widespread somatostatin-avid disease involving the left carotid bulb mass, bilateral lung nodules, and liver metastases, with the largest in the right hepatic lobe measuring 8 × 7 cm. There were peripancreatic lymph nodes and scattered skeletal metastases. The patient sought a second opinion, on the basis of which she was prescribed pazopanib, to which she showed a dramatic clinical response after 1 month, followed by a durable response for 1 year. Tyrosine kinase inhibitors such as pazopanib are potentially useful in paraganglioma, with further studies needed to understand the role of vascular endothelial growth factor receptor-directed kinase inhibitors in this setting.