Current status of intermittent androgen suppression in the treatment of prostate cancer.

Treatment of advanced prostate cancer by continuous androgen suppression results in excellent short-term response but poor long-term survival. Intermittent androgen suppression (IAS) aims to maintain androgen responsiveness of tumor cells by regular cycles of treatment cessations and tumor regrowth to specific prostate-specific antigen limits. First clinical trials demonstrate consistent responses and improved quality of life in most patients on androgen suppression retreatment for up to five cycles, with mean off-treatment periods of approximately 5 to 16 months. Most patients with metastatic disease exhibit early disease progression or androgen independency under IAS, but a subgroup including patients with metastatic disease respond to a single androgen suppression cycle with off-treatment times for up to 48 months. In conclusion, IAS improves the quality of life in patients with primarily hormone-dependent tumors without adverse effects and seems to be most effective in patients with prostate cancer with asymptomatic biochemical progression and low tumor burden. Patients should be treated within the framework of randomized trials and characterized for survival and prognostic factors associated with response to IAS treatment.