A Study of the Effect of Enantone LP 11.25 mg (Leuprorelin) on the Histological Progression of Indolent Prostate Cancer

Inclusion Criteria:

1. Is an out-patient 50 to 80 years old.
2. Has read, understood, signed and dated the informed consent.
3. Has indolent prostate cancer defined by:

   * Clinical Stage T1c or T2a.
   * Biopsy cores of which at least 12 reveal the presence of positive cores and the absence of cores with tumor length \> 3 mm.
   * Absence of Grade 4 cells (Gleason \<7).
   * Prostate specific antigen (PSA) levels \<10 ng/ml.
4. Has a life expectancy \> 5 years.
5. Has accepted the principle of active surveillance.
6. Is willing to participate in the study for a minimum of fifteen months.

Exclusion Criteria:

1. Has prior androgen deprivation including a 5-alpha reductase inhibitor (finasteride or dutasteride) within the last 6 months.
2. Has psychological failure related to prostate cancer therapy.
3. Has any active disorder likely to affect the conduct of the study or the patient's prognosis during the study.
4. Has a mental deficiency or any other reason that may hinder the understanding or strict application of the protocol.
5. Is under judicial protection, tutorship or curatorship.
6. Is unlikely to attend control visits.
7. Is currently enrolled in an investigational study or has participated in another investigational study within the last 3 months.
8. Has an allergy or hypersensitivity to any components of leuprorelin (Enantone LP) 11.25 mg or Casodex® 50 mg.
9. Has a medical history of severely impaired hepatic function linked to bicalutamide or a pathological cause.
10. Has testosterone level \< 0.5 ng/ml.