Sunitinib malate as first-line treatment for an advanced, poorly differentiated pancreatic neuroendocrine tumor.

Pancreatic neuroendocrine tumors (PNETs) are rare, accounting for approximately 2% of primary malignant tumors of the pancreas. Compared with common pancreatic ductal adenocarcinomas, they grow more slowly, are less invasive and have a better prognosis. At present, surgery is the preferred method of treatment of PNETs, and offers the only chance of a cure. However, owing to the occult onset of PNETs, once diagnosed they are often inoperable when the diagnosis is established, and the optimal treatment of patients with inoperable liver metastases remains uncertain. In recent years, targeted drug therapies have emerged and have proved effective in prolonging progression-free survival in patients with advanced well-differentiated PNETs, but hardly any progress has been made in the treatment of poorly differentiated PNETs. In the patient described in this report, who had a poorly differentiated PNET with multiple hepatic metastases and had refused cytotoxic chemotherapy, oral sunitinib malate treatment for 22 months with regular follow-ups proved tolerable and effective in significantly reducing the size of the intrahepatic masses.