This is a prospective, single arm, phase II, multicentric study. It evaluates the acute and late toxicity after stereotactic radiotherapy in low risk prostate cancer patients. All participants receive a total dose of 36.25 Gy in 5 fractions, twice a week, 7.25 Gy per fraction.

Inclusion Criteria:

• Histology of prostate adenocarcinoma
• Age≥ 18 years
• Life expectancy≥ 10 years
• Clinical negative nodes (N0)
• No metastasis presence (M0)
• No previous pelvic radiation therapy
• Total PSA≤10 ng/ml
• Gleason score ≤ 6
• T1-2
• ≤ 3 positive biopsy at prostatic mapping
• Signed informed consent

Exclusion Criteria:

• Positive nodes (N+) or metastatic disease (M+)
• Inflammatory bowel disease, collagen- vascular disorders or active autoimmune disorders
• Anticoagulant treatment in progress
• Hip or pelvic presence of medical devices that could prevent a correct image acquisition
• Symptomatic haemorrhoidal disease
• Adverse reactions to iodinate or paramagnetic contrast media
• Previous malignant cancer, except basocellular skin tumour or other tumours healed since 5 years
• Previous pelvic radiotherapy
• Psychiatric disorder that preclude to obtain informed consent