The principal objectives of the RADAR trial is to address the hypotheses; 1) that 18 months androgen deprivation in conjunction with radiotherapy is superior to 6 months androgen deprivation prior to and during radiotherapy; 2) that 18 months Bisphosphonate therapy will prevent bone loss caused by androgen deprivation therapy and further reduce relapse risk by impeding the development of bony metastases.
Inclusion Criteria: * Histological confirmation of adenocarcinoma of the prostate in the three months prior to randomisation * Gleason primary and secondary pattern reported. If the volume of tumour in biopsies is too small for the pathologist to allocate a secondary pattern, the primary pattern alone is sufficient. * Primary tumour stage T2b - 4 (UICC 2002), or T2a providing biopsies demonstrate Gleason score 7 or more, and presenting PSA 10 or more * PSA value obtained within one month of randomisation * No evidence of lymphatic or haematogenous metastases, as determined by negative chest x-ray, CT scan of abdomen and pelvis, and bone scan in the 3 months prior to randomisation * ECOG performance status 0 - 1 * No concurrent medical conditions likely to significantly reduce prospects of 5 year survival * Patient accessible to follow up at intervals specified in protocol * Written informed consent given (signed by both patient and investigator prior to randomisation) Exclusion Criteria: * Previous or concurrent malignancy within previous 5 years except for non-melanomatous skin cancer * Prostatectomy * Prior pelvic radiotherapy * Prior hormone treatment for prostate cancer * Inability to complete self administered QOL questionnaire * Prior bisphosphonate therapy * Serum creatinine \> 2 x ULN * Osteoporosis resulting in \>30% loss in vertebral height in one or more thoraco-lumbar vertebrae * Liver disease resulting in ALT or AST levels \>3 x ULN * Prolonged continuous glucocorticoid therapy \> 10 mg/day of prednisone equivalent (\>6 months) * Current treatment with bisphosphonate * Inability to attend for follow-up at the Investigator's clinic