The purpose of this study is to compare the effects, good and/or bad, of temozolomide versus temozolomide plus capecitabine on the subjects and the subjects’advanced pancreatic neuroendocrine tumor cancer to find out which is better. In this study, subjects will get either temozolomide alone or temozolomide and capecitabine. Temozolomide and capecitabine are chemotherapy drugs, which have benefited some patients with pancreatic neuroendocrine tumors yet they have never been compared; both arms are considered investigational.
