- PSA progression defined as two consecutive increases in PSA value over the previous reference value; the first increase of PSA should occur no earlier than one (1) week after the reference measurement; all patients need to demonstrate continued PSA elevation with an increasing PSA four weeks after the required cessation of their antiandrogen treatment; the required cessation period is 4 weeks for flutamide, nilutamide, and Megace-based treatment, and 8 weeks for bicalutamide-based treatment