Rosiglitazone in Treating Patients With Locoregionally Extensive or Metastatic Thyroid Cancer

DISEASE CHARACTERISTICS: Diagnosis of differentiated thyroid cancer Locoregionally extensive and/or metastatic disease Inoperable disease Failed prior conventional therapy that included total/near-total thyroidectomy AND radioactive iodine I 131 ablation therapy Elevated thyroglobulin (Tg) levels (> 3 ng/mL on thyroid hormone OR > 10 ng/mL off thyroid hormone) Tg-antibody positive patients are eligible despite the Tg level Radioactive iodine (RAI) scan showing no or therapeutically insignificant (< 1%) RAI uptake after thyroid hormone withdrawal Scan performed within the past 18 months PATIENT CHARACTERISTICS: Age 18 and over Performance status Not specified Life expectancy Not specified Hematopoietic Hemoglobin ≥ 10 g/dL WBC ≥ 3,000/mm^3 Platelet count ≥ 50,000/mm^3 Hepatic ALT ≤ 2 times upper limit of normal Renal Creatinine ≤ 1.5 mg/dL Cardiovascular No New York Heart Association class III or IV cardiac disease Other Not pregnant No nursing within the past 3 months Negative pregnancy test Fertile patients must use effective contraception No allergy to thiazolidinediones No other malignancy except basal cell skin cancer PRIOR CONCURRENT THERAPY: Biologic therapy Not specified Chemotherapy More than 3 months since prior chemotherapy Endocrine therapy See Disease Characteristics No concurrent levothyroxine Radiotherapy See Disease Characteristics No prior cumulative dose of radioiodine ≥ 800 mCi Prior adjuvant or therapeutic external beam radiotherapy allowed Surgery See Disease Characteristics