Most men respond to initial ADT with a fall in serum PSA and improvement in symptoms, if present initially; the median duration of response is about 1.5 - 2 years, but is highly variable. Increase in serum PSA despite a castrate testosterone level signifies that the disease has become castration resistant. Some patients may have short periods of response to other hormonal manipulations such as adding a peripheral antiandrogen such as bicalutamide, and later withdrawing it. Other hormonal manipulations may be tried sequentially before or after chemotherapy with varying success: this tertiary hormonal manipulation may include glucocorticoids such as prednisone or dexamethasone, ketoconazole and hydrocortisione, estrogens such as DES, and alternative anti-androgens such as flutamide and nilutamide. In most institutions, the policy is to continue the LHRH agonist indefinitely. Despite its proven role in prostate cancer treatment, ADT has multiple toxicities which include osteopenia/osteoporosis, a potentially lethal metabolic syndrome and cardiovascular complications. Also, continuous long term LHRH injections are very expensive.
In this study, we propose a prospective cohort study at Princess Margaret Hospital to answer the following important questions regarding tertiary hormonal manipulations:
1. What is the relationship between serum testosterone and time after stopping an LHRH agonist in men who have received chronic LHRH therapy for ≥ 1 year?
2. What clinical factors influence recovery of testosterone?
3. What is the saving of cost achieved by dosing the LHRH agonist on the basis of measurement of testosterone as compared to routine 3-monthly injection?
