In prior studies with men who have had a PSA recurrence after radiotherapy (RT), intermittent androgen suppression (IAS) has been suggested to improve quality of life (QoL) but effects on survival are unknown.

The researchers performed an inter-group randomized phase III trial, which compared IAS vs continuous androgen deprivation (CAD) to test overall survival (OS) differences between the two therapies.

All subjects had rising PSA greater than 3.0 ng/ml in a time period greater than1 year post RT, RT was either initial or salvage or for localized prostate cancer. The men could receive up to 1 year of neo/adjuvant androgen deprivation therapy (ADT) completed longer than 1 year prior.

Stratification factors were time since RT (> 1-3 vs > 3 years), initial PSA (>15 vs > 15), prior radical prostatectomy and prior ADT. IAS was delivered for 8 months in each cycle with restart when PSA reached >10 ng/ml off treatment.

Primary endpoint was overall survival (OS); secondary endpoints include