Long-Term Efficacy of S-1 Chemotherapy plus Administration of Octreotide for a Patient with Metastatic Neuroendocrine Tumor (Gastrinoma)

Metastatic neuroendocrine tumors (gastrinomas) have a poor prognosis. Octreotide can reduce gastrin levels and alleviate hormonal symptoms, and possibly slow tumor growth as well. No drugs were available except streptozocin for the treatment of metastatic pancreatic neuroendocrine tumor (PNET) in 2008. We report a case of PNET in a 53-year-old woman with multiple liver tumors treated with S-1 plus octreotide. After 6 months from the initiation of the treatment, the pancreatic tumor and liver metastases regressed, and the patient achieved partial response without the development of any serious adverse event. For more than 8 years, the patient has remained asymptomatic without disease progression and is continuing treatment with octreotide and S-1. A marked suppression of gastrin levels has also been achieved. Combination therapy with octreotide and S-1 has been effective and well tolerated in patients with metastatic gastrinoma.