Androgen deprivation therapy in advanced prostate cancer: is intermittent therapy the new standard of care?

Purpose Intermittent androgen deprivation is increasingly used as an alternative to continuous life-long androgen deprivation therapy for men with advanced or recurrent prostate cancer. Recent Findings Two recent phase in trials have clarified the benefits of intermittent therapy. The Canadian-led PR.7 trial in men with nonmetastatic disease and prostate-specific antigen recurrence after definitive local therapy showed that intermittent therapy resulted in survival equivalent to that with continuous therapy, with significant improvements in quality of life. Patients on intermittent therapy experienced improved bone health, fewer metabolic and hematologic disturbances, fewer hot flashes, and improved sexual function. In men with metastatic disease, the data are less clear. The long-awaited results of the Southwest Oncology Group 9346 trial, comparing intermittent with continuous therapy in metastatic disease, showed no difference in overall survival. Post hoc stratification analysis showed a worse outcome in patients with minimal metastatic disease, and no difference in those with widespread bone metastases. The significance of that observation is in dispute. The present review also addresses practical issues in the use of intermittent therapy, including patient selection, follow-up, and therapy cycling. Summary The recent results of randomized clinical trials now establish that intermittent androgen deprivation therapy is an approach that should be considered the standard of care in most patients with non metastatic prostate cancer requiring hormonal therapy and in selected patients with metastatic disease.