The continued debate: Intermittent vs. continuous hormonal ablation for metastatic prostate cancer

Objectives: To summarize the debate regarding use of intermittent androgen suppression therapy in the treatment of prostate cancer originally presented at the 2007 Spring Meeting of the Society of Urologic Oncology. Methods: The debate was framed within the context of known toxicities of therapy and impact on quality of life. Arguments for and against IAS were summarized. Results: IAS appears to be a reasonable treatment approach for men with advanced prostate cancer except those with high risk features including PSA > 20, or bone metastatic disease. Men with TxN1-3M0 who are sexually active, compliant to close follow-up, or who do not tolerate the side effects of androgen ablation can be considered for IAS as long as they realize it is investigational. There is not a clear consensus upon duration of treatment, interval between treatment cycles, or appropriate PSA nadir, but it does appear that PSA nadir > 4 ng/ml may predict a poor outcome. Based on time to PSA nadir and changes in expression of proliferation markers staining, treatment duration of 6 to 9 months is recommended prior to stopping therapy. Trigger points for restarting therapy are individualized, and factors that are considered include pretreatment PSA levels, stage, PSA velocity, presence of symptoms, and tolerance of androgen ablation therapy. Conclusions: IAS should be considered in the management of men with advanced prostate cancer and no evidence of bone metastases. While intermittent therapy is feasible and offers potential improvement in quality of life, it is not yet shown that it reverses the long-term side effects of androgen suppression.