Improving intermittent androgen deprivation therapy： lessons learned from basic and translational research

Intermittent androgen deprivation therapy （IADT） is an alternative to continuous androgen deprivation therapy （ADT） in prostate cancer patients with nonmetastatic disease. ADT is associated with numerous side effects such as hot flashes, sexual dysfunction, anemia, fatigue, loss of muscle mass, osteoporosis, metabolic syndrome and premature cardiovascular disease. IADT was developed with the intention of improving the quality of life and to delay progression of prostate cancer to castration resistance. The benefits of slightly improved quality of life by IADT compared to ADT were demonstrated in multiple clinical trials. IADT was noted to be noninferior to ADT in patients with biochemical recurrence of prostate cancer but in studies performed in patients with metastatic prostate cancer, the results were inconclusive. Our recent studies suggested that the administration of 5 alpha-reductase inhibitors during the off-cycle of IADT can significantly prolong the survival of mice bearing androgen-sensitive prostate tumors when off-cycle duration was short. This review discusses the survival benefit of 5 alpha-reductase inhibition in IADT in animal models and the potential translation of this finding into clinic.

Intermittent androgen deprivation therapy in patients with prostate cancer: Connecting the dots

Intermittent androgen deprivation therapy(IADT)is now being increasingly opted by the treating physicians and patients with prostate cancer.The most common reason driving this is the availability of an off-treatment period to the patients that provides some relief from treatment-related side-effects,and reduced treatment costs.IADT may also delay the progression to castration-resistant prostate cancer.However,the use of IADT in the setting of prostate cancer has not been strongly substantiated by data from clinical trials.Multiple factors seem to contribute towards this inadequacy of supportive data for the use of IADT in patients with prostate cancer,e.g.,population characteristics(both demographic and clinical),study design,treatment regimen,on-and off-treatment criteria,duration of active treatment,endpoints,and analysis.The present review article focuses on seven clinical trials that evaluated the efficacy of IADT vs.continuous androgen deprivation therapy for the treatment of prostate cancer.The results from these clinical trials have been discussed in light of the factors that may impact the treatment outcomes,especially the disease(tumor)burden.Based on evidence,potential candidate population for IADT has been suggested along with recommendations for the use of IADT in patients with prostate cancer.