DISEASE CHARACTERISTICS: Histologically proven, recurrent or metastatic, adenocarcinoma or adenosquamous carcinoma of the endometrium not curable by surgery and/or radiotherapy Failed one prior progestin therapy for advanced/metastatic disease OR Considered for letrozole as first line therapy of advanced/metastatic disease No clear cell or papillary serous histology, uterine sarcomas, mixed muellerian tumors, and/or adenosarcomas At least one site of measurable disease by clinical exam, CT, or MRI scan Bone lesion(s) are not considered measurable No CNS metastases