Letrozole Versus Observation in Patients With Newly Diagnosed Uterine Leiomyosarcoma

Letrozole is an aromatase inhibitor. Aromatase is the enzyme that produces estrogen in post-menopausal women. By interfering with the production of estrogen triggered by aromatase, letrozole reduces the total amount of estrogen in the body. As a result, less estrogen can reach cancer cells, thus preventing their growth. Before you can start treatment on this study, you will have "screening tests." These tests will help the doctor decide if you are eligible to take part in this study. These exams, tests, or procedures are part of regular cancer care and may be done even if you do not join the study. If you have had some of them recently, they may not need to be repeated. This will be up to your study doctor. Your complete medical history will be recorded, and you will have a physical exam (including a pelvic exam). Your vital signs and blood pressure will be measured. Blood (about 2-3 teaspoons) will be drawn for routine tests. You will also have a blood test (1 teaspoon) to check your cholesterol. You will have an electrocardiogram (ECG -- a test that measures the electrical activity of the heart). You will also have a chest x-ray, and either a computed tomography (CT) scan or a magnetic resonance imaging (MRI) to check the status of the disease. Your doctors will test previously collected tumor tissue to learn if the estrogen receptor is positive or negative. If you are found to be eligible to take part in this study, you will be randomly assigned (as in the toss of a coin) to 1 of 2 groups. Group 1 will receive letrozole by mouth once a day. Group 2 will receive no treatment. Both groups will be followed closely every 3 months. You will have an equal chance of being placed in either group. If you are in Group 1, you will take letrozole by mouth every day for 12 weeks. Every 12 weeks is considered a study "cycle." You will only be given the amount of drug needed for 1 cycle of therapy at a time. You will keep a diary during the study that will list when and how much drug you took. This diary will be reviewed after each cycle of therapy by the research nurse or doctor and filed in your chart. Every 12 weeks, all participants will have blood (about 3-4 teaspoons) drawn for routine tests. CT scan of the chest, abdomen (stomach area), and pelvis will be done every 24 weeks. In addition, all participants will have a physical exam (including a pelvic exam), and your vital signs and blood pressure will be measured. You may remain on study for as long as you are benefitting. You will be taken off study if intolerable side effects occur. Once you are off study, blood (about 2-3 teaspoons) will be drawn for routine tests and to measure your cholesterol level. You will have a physical exam (including a pelvic exam), and an MRI or CT scan. This is an investigational study. Letrozole is approved by the FDA for treatment of some breast cancer patients after surgery. Its use in patients with leiomyosarcoma is experimental. Up to 80 patients will take part in this study. All will be enrolled at M. D. Anderson.