The purpose of this study is to compare the efficacy and safety of combined radiotherapy and hormone therapy and hormone therapy alone in the treatment of clinically locally advanced prostate cancer (T3-T4 or pT3 on biopsy, N0, M0).

The drug being tested in this study is called leuprorelin SR. Leuprorelin SR is being tested to treat people who have prostate cancer. This study will look at the overall survival of people who take leuprorelin SR in addition to radiation therapy compared to those who take only leuprorelin SR.

The study will enroll approximately 273 patients. Participants will be randomly assigned to one of the two treatment groups.

• Combined Radiotherapy and Hormone Therapy
• Hormone Therapy alone. All participants will receive leuprorelin injection every 3 months and flutamide tablets thrice daily for first 30 days as part of hormone therapy. Participants randomized to combined radiotherapy and hormone therapy group, will also receive radiotherapy 70 +/- 4 Gy in 35 fractions at a rate of 5 fractions of 2 Gy per week.

This multi-center trial will be conducted in France and Tunisia. The overall time to participate in this study is 8 years. The scheduled duration of hormone therapy was 3 years in both arms, with an additional treatment-free follow-up period of 2 years i.e. a total follow-up period of 5 years. Post-protocol collection of information relative to survival will be performed after the end the 5-year follow-up period.

Inclusion Criteria:

• Histologically confirmed locally advanced adenocarcinoma of the prostate, graded: T3 or T4 or pT3 on biopsies (presence of tumour tissue in periprostatic fat observed on biopsies), N0 (absence of metastatic), M0 (no distant metastases detectable on the following examinations: bone scan, chest x-ray, abdominal and pelvic ultrasound).
• Patient in whom the prostatic adenocarcinoma has received no prior treatment of any type, with the possible exception of transurethral resection due to obstructive symptoms.
• Patient with a Karnofsky index greater than or equal to (≥) 70.
• Patient aged under 80 years on the randomization date.
• Patient with a life expectancy of at least 7 years.
• Patient who, after having received clear information, gave his written consent to participate and cooperate in the study.
• Patient for whom a recent blood test (less than [<] 2 months) has not revealed elevated transaminases ≥ 3 times the normal laboratory range.

Exclusion Criteria:

• Patient incapable of understanding the information supplied concerning the study or of giving his consent, or having refused to sign the informed consent form,
• Patient for whom there is a risk that follow-up in compliance with the conditions stipulated by the protocol will not be possible,
• Patient having already received prior treatment for prostate cancer, excluding transurethral resection of the prostate to relieve obstruction,
• Patient having undergone surgical castration, or with a history of bilateral adrenalectomy or hypophysectomy,
• Patient having had another cancer within the previous 5 years (including carcinoma in situ of the bladder) excluding basocellular epithelioma or carcinoma in situ (other than in the bladder),
• Patient with lymph node or metastatic spread of the prostatic adenocarcinoma suspected on imaging,
• Patient with a non-controlled severe active disease,
• Patient with a contraindication to external prostatic radiotherapy,
• Patient receiving or having received another experimental treatment within 3 months prior to inclusion in the study,
• Patient with impaired liver function or elevated transaminases ≥3 times the normal laboratory range.