Hypo-Combi Trial: Hypofractionated EBRT Plus HDR-BT Boost for Prostate Cancer

Inclusion Criteria: * The patient must consent to be in the study and must have signed an approved consent form * Age \> 18 years old. * Life expectancy of at least five years, excluding his diagnosis of prostate cancer. * Histopathologically proven primary adenocarcinoma of the prostate * The patient must be registered within 180 days following the histopathological confirmation of the malignancy * Prostate volume \< 80ml * International Prostate Symptom Score (IPSS) \< 18 * Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2 * Patients with a history of non-prostate malignancies are eligible if they have been disease-free for 5 or more years prior to enrolment, are deemed by their physician to be at low risk for recurrence and they did not need pelvic radiotherapy as part of their treatment. Patients with the following cancers are eligible if diagnosed and treated within the past 5 years: carcinoma in situ of the colon, melanoma in situ, and basal cell and squamous cell carcinoma of the skin. Exclusion Criteria: * Histopathological confirmation or suspicion in conventional or molecular imaging of regional or distant metastases * Prior pelvic radiotherapy * Known autoimmune disorders (e.g. inflammatory bowel disease, lupus, scleroderma) * Prior TURP * MRI non compatible metal implants * Pre-existing fistulae * Contraindication for general and spinal anaesthesia * Inability to be placed in lithotomy position * Any treatment with radiation therapy, chemotherapy, immunotherapy, biotherapy and/or hormonal therapy for the currently diagnosed prostate cancer prior to registration. * History of non-prostate malignancy, apart from patients that have been disease-free for 5 or more years prior to randomization and are deemed by their physician to be at low risk for recurrence. * Psychiatric or addictive disorders or other conditions that, in the opinion of the investigator, would preclude the patient from meeting the study requirements.