Capecitabine and Temozolomide for Treatment of Recurrent Pituitary Adenomas

Inclusion Criteria:: * Male or female ≥ 18 years of age. * Patients with nonfunctioning tumors must have histologically confirmed pituitary adenoma. Patients with functioning tumors do not require surgery if there is clear diagnosis of functioning pituitary adenomas established based on endocrine evaluation. * Karnofsky performance status ≥ 70%. * Life expectancy of greater than six months. * Residual or recurrent pituitary adenoma ≥1cm in maximal diameter on MRI Brain; patient must have received at least one prior therapy, such as surgery, radiation and/or medical therapy. * Patients must have normal organ and marrow function as defined below. NOTE: Laboratory values must be taken within 7 days prior to chemotherapy administration. Transfusions and/or growth factor support may not be used to meet this criteria): * Platelet count ≥ 100 × 109/L. * Hemoglobin ≥ 9 g/dL. * WBC ≥ 3 × 109/L * Absolute neutrophil count (ANC) ≥ 1.5 × 109/L. * Serum bilirubin ≤ 1.5 × upper limit of normal (ULN) or ≤ 3 x ULN if Gilbert's disease is documented. * Aspartate transaminase (AST) ≤ 2.5 ULN. * Alanine transaminase (ALT) ≤ 2.5 ULN. * Serum creatinine ≤ 1.5 × ULN OR creatinine clearance≥60mL/min/1.73 m2 for patients with creatinine levels above institutional normal. * Patients must be able to undergo a MRI Brain/Pituitary * For women of child-bearing potential and for men with partners of child-bearing potential, subject must agree to take contraceptive measures for duration of treatment and at least 6 months after the last dose of chemotherapy. * Patients must have the ability to understand and the willingness to sign a written informed consent document. Exclusion Criteria: * Prior temozolomide and/or capecitabine therapy for treatment of the pituitary tumor. * Other active malignancy outside of nonmelanoma skin cancer (patients in remission and with prior treatment more than two years ago will be accepted into trial). * Clinically significant renal, hematologic or hepatic abnormalities. * Use of Vitamin K antagonists such as warfarin (concentrations may be altered by concomitant use of capecitabine) * Uncontrolled concurrent illness including, but not limited to, ongoing or active infection requiring IV antibiotics \& psychiatric illness/social situations that would limit compliance with study requirements * History of deficient dihydropyrimidine dehydrogenase activity. * History of immunodeficiency. * Patients who are taking any other concurrent investigational therapy. * Patients who are pregnant or breastfeeding. * Patients who have had prior radiation treatment in the last six months * Patients who have had prior pituitary surgery within the last two months