Testosterone in Castration-Resistant Prostate Cancer

Generally, castration therapy has been used indefinitely for prostate cancer patients because some tumors seem to grow faster with testosterone present. Researchers want to study the effect of testosterone only in patients whose tumors have had a maximum response to castration therapy. Researchers want to find out if these patients' disease may be better controlled with testosterone replacement therapy. 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. Your complete medical history will be recorded and there will be a review of all medicines you may be currently taking. You will have a physical exam, including measurement of your vital signs (blood pressure, heart rate, temperature, and breathing rate). You will have blood drawn (about 4 teaspoons) and urine collected for routine tests. You will have a chest x-ray, an electrocardiogram (ECG--a test to measure the electrical activity of the heart), a bone scan, and a computed tomography (CT) scan of your abdomen and pelvis. If the study doctor thinks it is necessary, you may have an assessment of your mental status. For this assessment, you will be asked questions about your attention span, memory, and mood disturbances. It will take about 25 minutes to complete. If you are found to be eligible to take part in this study, you will begin receiving testosterone enanthate replacement therapy every 2 weeks by an injection into a muscle. Every 2 weeks, you will go to the clinic for your testosterone injection, and blood (about 2 teaspoons) will be drawn to check the testosterone level in your blood. This will help the study doctor learn what dose you will receive for the next 2 weeks. After your Week 8 visit, blood (about 2 teaspoons) will be drawn to check the testosterone level in your blood every 4 weeks for the rest of your time on this study. At the Week 8 and 24 visits, you will have a physical exam, including measurement of your vital signs. You will be asked about any side effects you may be experiencing. Your disease status will be evaluated to learn its response to treatment. Blood (about 4 teaspoons) will be drawn for routine tests, and you will have repeat imaging scans (like the ones you had at your screening visit) to evaluate your disease. If the study doctor thinks that your mental status should be assessed again, you will have another assessment (at or around Week 24) like the one completed during your screening visit. You may remain on this study indefinitely unless your disease gets worse or you experience any intolerable side effects. If your participation ends on this study for any of the above reasons, you will have an end-of-study visit. During this visit, you will have blood drawn (about 4 teaspoons) for routine testing. You will be asked about any side effects you may be experiencing, and your disease response to treatment will be evaluated. This is an investigational study. Testosterone enanthate is commercially available. Testosterone replacement therapy is not FDA approved for this disease, and in some cases, has been disallowed for use in prostate cancer. Up to 40 patients will take part in this study. All will be enrolled at M. D. Anderson.