DISEASE CHARACTERISTICS:

• Histologically confirmed thyroid cancer

  • Progressive or refractory disease within the past 6 months
  • Locally advanced or metastatic disease
• Measurable disease, defined as ≥ 1 measurable lesion defined by RECIST criteria
• Not amenable to surgical resection or external-beam radiotherapy or refractory to radioiodine therapy
• No untreated brain metastasis

PATIENT CHARACTERISTICS:

• ECOG performance status 0-2
• Life expectancy > 3 months
• ANC ≥ 1,500/mm³
• Platelet count ≥ 100,000/mm³
• Hemoglobin ≥ 9.0 g/dL
• Creatinine < 1.5 mg/dL
• Total bilirubin ≤ 1.0 times upper limit of normal (ULN)
• ALT and AST ≤ 3.0 times ULN
• No known hypersensitivity to the study drug
• No serious uncontrolled systemic intercurrent illness (e.g., infection or poorly controlled diabetes)
• No history of significant neurological or mental disorder, including seizures or dementia
• No other malignancy within the past 5 years except for carcinoma in situ of the cervix or nonmelanomatous carcinoma of the skin
• No active uncontrolled cardiac disease
• No myocardial infarction within the past 12 months
• Able to take oral medication
• No active peptic ulcer disease
• Must have patient compliance and geographic proximity for adequate follow-up

PRIOR CONCURRENT THERAPY:

• At least 30 days since prior mTor-inhibitor therapy (e.g., temsirolimus) or non-hormonal anticancer therapy
• At least 2 weeks since prior and no concurrent P-glycoprotein, CYP3A4, and CYP3A5 inhibitors or inducers
• No prior surgical procedure affecting absorption
• No other concurrent systemic chemotherapy, investigational drug, or radiotherapy