Gonadotropin-releasing hormone agonists in prostate cancer: A comparative review of efficacy and safety

Androgen deprivation therapy (ADT) using gonadotropin-releasing hormone agonist (s) (GnRH-A) remains the backbone of advanced prostate cancer treatment. In this review, we assessed the efficacy, safety, and convenience of administration of various GnRH-A. All GnRH-A (goserelin, triptorelin, buserelin, histrelin, and leuprorelin) have comparable potential to suppress testosterone (T) levels (<= 50 ng/dL in a month and <= 20 ng/dL in 3 months). However, goserelin has shown better efficacy in maintaining T levels <= 50 ng/dL compared with leuprolide. The incidences of T escape are lower with goserelin and leuprolide than buserelin. Goserelin also has maximum benefit in prostate-specific antigen suppression. In neoadjuvant setting, when only goserelin was used, the 10-year overall survival (OS) rate was 42.6% to 86%. When either goserelin or leuprolide was used, the 10-year OS rate was 62%. As an adjuvant to radical prostatectomy, goserelin had a 10-year survival rate of 87%, and triptorelin had an 8-year survival rate of 84.6%. Goserelin further showed an absolute survival rate of 49% when used as an adjuvant to radiotherapy. The survival rates further improved when GnRH-A are used as combined androgen blockade compared with monotherapy. The frequency and severity of adverse events (hot flushes, fatigue, sexual dysfunction) are comparable among the GnRH-A. Goserelin appears to be the most convenient of all the GnRH-A for administration. Lack of conclusive comparative evidence makes it imperative to have a holistic approach of considering the patient profile and the disease characteristics to select the appropriate GnRH-A for ADT in prostate cancer.