Capecitabine and Temozolomide for Neuroendocrine Cancers

Inclusion Criteria:

* Patients must have a tissue diagnosis of any of the following metastatic, well or moderately differentiated, slow growing neuroendocrine tumor and must demonstrate progressive metastatic disease by prior serial computerized tomography (CT) or magnetic resonance imaging (MRI) scans, or have increased symptoms from their tumors while on sandostatin LAR or octreotide.
* Carcinoid tumors originating anywhere in the body including the gastrointestinal (GI) tract or bronchial tree
* Pancreatic neuroendocrine tumors (including functional and non-functional islet cell, insulinomas and glucagonomas)
* Pheochromocytomas, gastrinomas (Zollinger-Ellison Syndrome), multiple endocrine neoplasia (MEN) Type I/II, paragangliomas, adrenal carcinomas with NET markers by immunohistochemistry (IHC) or serum.
* Somatostatinoma, VIPoma, Merkel Cell tumors, medullary thyroid carcinoma
* Neuroendocrine tumors of unknown primary site
* Any other tumors with differentiated neuroendocrine features may be included such as aggressive pituitary adenomas/carcinomas, which are neuroendocrine in origin
* Patients must have progressed on octreotide therapy (up to and including Sandostatin LAR-60 mg/month) and/or radioactive isotopes linked to octreotide or its congeners if they has a positive octreotide scan. Patients who have negative or mildly positive octreotide scans are exempt from this requirement. Exceptions to this requirement are patients who have NETs in the pituitary gland. Sandostatin does not cross into the pituitary blood supply well.
* Measurable disease: Any primary and/or metastatic mass reproducibly measurable in one or two diameters by Response Evaluation Criteria In Solid Tumors (RECIST) parameters by CT scan or MRI scan.
* Ineligible for other high priority national or institutional studies
* Prior radiation and surgery allowed: ≥3 weeks since surgery or chemotherapy or hepatic embolization/chemoembolization or radioactive isotopes (i.e. Yttrium 90) ≥4 weeks since radiation therapy (RT)
* Non pregnant females, not in menopause, who are not breast feeding with a negative serum β-HCG (human chorionic gonadotropin) test within 1 week of starting the study. Men and women of childbearing potential must consent to using effective barrier contraception while on treatment and for 2 months thereafter.

Exclusion Criteria:

* Prior chemotherapy with capecitabine or temozolomide. Patients previously treated with continuous infusion 5-FU or any schedule of DTIC (dacarbazine), which are similar to capecitabine and temozolomide, respectively, will be excluded. Patients can have had prior therapies up to 3 prior chemotherapy regimens such as bolus 5-FU, streptozocin, anthracyclines, Camptothecin-11 (CPT-11), etoposide, or a platinum agent
* Hypersensitivity: Patients with a history of severe hypersensitivity reaction to capecitabine, 5-FU, temozolomide or DTIC will be excluded (i.e. anaphylaxis or anaphylactoid reactions)
* Serious medical or psychiatric illness preventing informed consent or intensive treatment (e.g, serious infection)
* Patients with tumor which has spread to the central brain (cerebral/cerebellum) and spinal cord.
* Patients with compromised immune systems are at increased risk of toxicity and lethal infections when treated with marrow-suppressive therapy. Therefore, HIV-positive patients are excluded from the study
* Prior malignancies in the last 5 years other than; curatively treated carcinoma in-situ previously treated with curative intent (cancer free for the past year)