- More than 4 weeks since prior and no concurrent estrogens, estrogen-like substances (i.e., PC-SPES, saw palmetto, or other herbal product that may contain phytoestrogens), or any other hormonal therapy (including flutamide, nilutamide, finasteride, ketoconazole, systemic corticosteroids, megestrol acetate, or cyproterone acetate)