Intermittent androgen deprivation for locally advanced prostate cancer - Preliminary experience from an ongoing randomized controlled study of the South European Urooncological Group

Approximately 80% of prostate cancer patients achieve symptomatic and objective responses following androgen suppression, and serum prostate specific antigen (PSA) levels decrease in almost all patients. Surgical or medical castration results in a median progression-free survival of 12-33 months and a median overall survival of 23-37 months in patients with stage M1 disease. However, for reasons that remain unknown, the cell death process induced by androgen ablation, by whatever means, fails to eliminate the entire malignant cell population [1]. Another limitation of conventional androgen ablation is that it increases the rate of progression of prostate cancer to an androgen-independent state [1], and, after a variable period of time averaging 24 months, the tumor inevitably recurs with increasing serum PSA levels and is characterized by androgen-independent growth. Over the past 20 years, most efforts have focused on maximizing the degree of androgen suppression therapy by combining agents that inhibit or block both testicular and adrenal androgens. However, maximal androgen ablation increases treatment-related side effects and expenses, while prolonging disease-free interval by 3-6 months in most patients [2].