The Impact of Obesity and Obesity Treatments on Breast Cancer

The Study Drugs: Exemestane decreases the ability of estrogen to help cancer cells grow. This could cause the cancer cells to die. Avandamet contains two drugs commonly used to control blood sugar levels in patients with diabetes (metformin and rosiglitazone). If you are found to be eligible to take part in this study, the dose of Avandamet you receive will depend on when you joined this study. The first group of participants will receive the lowest dose level of Avandamet. Each new group will receive a higher dose of Avandamet than the group before it, if no intolerable side effects were seen. This will continue until the highest tolerable dose of Avandamet is found. All participants will receive the same dose level of exemestane. Study Drug Administration: The study drug(s) will be given in 28-day "cycles." You will take an exemestane tablet by mouth every day. You will also take tablets of Avandamet by mouth 1 or 2 times a day depending on the dose level to which you are assigned. You should take Avandamet at meals. Study Visits: On Day 1 of Cycles 2, 3, and 4, and then every 3 months after that, the following tests and procedures will be performed: * You will have a physical exam, including a measurement of your weight and vital signs. * You will be asked about any side effects you may be having. * You will be asked about any drugs you may have taken or may be taking. * You will have a performance status evaluation. * Blood (about 1-2 teaspoons) will be drawn for routine tests. This blood draw can be done up to 3 days before each cycle. * Blood (about 1 teaspoons) will be drawn for blood sugar tests. If you have a history of diabetes, you will need to fast for 8 hours before these blood sugar tests. Every 3 months, you will have scans to check the status of the disease. The scan performed will depend on where the disease is located in the body. Every 3 months, you will also have an echocardiogram (ECHO) or a multi-gated acquisition (MUGA) scan to test your heart function. Additional Blood Draws: Blood (about 1 teaspoon each time) will also be drawn for pharmacokinetic (PK) testing. PK testing measures the amount of study drug(s) in the body at different time points. Blood will be drawn for PK testing before you take the study drug(s) and 1, 3, 6, 12, and 23 hours after you take the study drug(s) on Days 1, 8, and 15 of Cycle 1. Length of Study: You may take the study drug(s) for as long as the disease is stable and/or responding. You may be taken off study if the disease gets worse or intolerable side effects occur. This is an investigational study. Exemestane and Avandamet are FDA approved and commercially available. Exemestane is approved for the treatment of metastatic breast cancer. Avandamet is approved for the treatment of diabetes. The use of this drug combination is investigational. Up to 24 patients will take part in this study. All will be enrolled at M. D. Anderson.