A Randomised, Double-Blind, Placebo-Controlled Trial Assessing the Efficacy and Safety of Dutasteride (AVODART™) 0.5 mg in Extending the Time to PSA Doubling in Men with Prostate Cancer and Biochemical Failure (PSA increase) after Radical Therapy with Curative Intent (ARTS - AVODART after Radical Therapy for prostate cancer Study)