The objective of this study is to use as a reference the 36-month duration of hormonal therapy according to the European Organization for Research of the Treatment of Cancer (EORTC protocol 22863) : namely one-month of total androgen blockade followed by a luteinizing hormone releasing hormone (LHRH) agonist, all for three years, combined with pelvic and prostate irradiation; this arm is currently considered to be a standard for high-risk prostate cancers. The proposed study intends to challenge the duration of hormonal therapy and verify whether the five-year outcomes in favour of combined treatment in regard to survival (79% versus 62%) and local control (85% versus 48%) can be transposed for hormonal therapy that is half as long, namely 18 months, with the possibility of hormone salvage therapy in the event of biochemical and/or clinical failure (local, regional, or distant); this applies to both arms. The proposed study will compare survival in the two groups and evaluate in each one the total duration of initial hormonal therapy, followed by initial hormonal therapy combined with salvage hormonal therapy, the duration of salvage hormonal therapy until hormonal therapy resistance, and the side effects of this hormonal therapy, with everything being related to an assessment of the quality of life of these patients.