After lung cancer, prostate cancer is the most common cause of death among males. The American Cancer Society estimates that 234,460 new cases of prostate cancer were diagnosed, and 27,350 men died from this disease in the United States in 2006 (ACS 2006). Treatment for early stage prostate cancer that is believed to be confined to the prostate gland include: radical prostatectomy, external beam or interstitial radiation therapy, and watchful waiting. Androgen suppression therapy (AST) to reduce circulating serum testosterone and disease progression is considered a mainstay of treatment for men with advanced prostate cancer.
Five studies involving 1382 patients were included in this review. All the included studies involved advanced (T3 or T4) prostate cancer. No study was of adequate size and duration. Few events were reported and they did not assess disease-specific survival or metastatic disease. Only one study evaluated biochemical outcomes. Studies primarily reported on adverse events. There are no data for the relative effectiveness of IAS versus CAS for overall survival, prostate cancer specific survival, disease progression, or quality of life. Limited information suggests IAS may have slightly reduced adverse events. In Hering 2000, IAS (18/25 versus 18/18) appears to be slightly more favorable than CAS in controlling impotence. Overall, IAS was also as effective as CAS for potency, but was superior during the interval of cycles (96%). More research is needed.