A Phase I-II Dose Escalation Study of Stereotactic Body Radiation Therapy in Patients With Localized Prostate Cancer

Inclusion Criteria:

* All patients must be willing and capable to provide informed consent
* Histologic confirmation of prostate adenocarcinoma
* T2-T3 tumors, N0 (clinically by no evidence of metastatic lymph nodes on CT or MRI)
* No direct evidence of regional or distant metastases
* PSA less than or equal to 50 μg/ml
* Visible gross tumor at the prostate endorectal coil MRI.
* The ultrasound or MRI based volume estimation of the patient's prostate gland no greater than 70g or 70cc
* No significant urinary obstructive symptoms; IPSS score must be ≤ 15 (alpha blockers allowed)
* Patient must have undergone an endorectal coil magnetic resonance image (MRI) of the prostatic gland (before rectal spacer if any),
* Patient must have undergone the following assessments in case of PSA ≥ 20μg/L, and/or T3 tumor and/or Gleason Score ≥ 8:

  * bone scan
  * Chest abdominal and pelvis computed tomography (CT) scan
* If tumor is localized at less than 3 mm from the rectum a rectal spacer is mandatory. Patient accepts the rectal spacer to be injected before treatment starts
* Patient accepts to have one planning MRI after the injection of rectal spacer (without endorectal coil)
* Patient accepts the preparation of the bladder (bladder full), before the planning MRI, planning CT and then before each treatment fraction

Exclusion Criteria:

* Previous radiotherapy in the pelvis
* Tumor localized at less than 3 mm from the urethra
* History of inflammatory colitis (including Crohn's disease and ulcerative colitis)
* Prior cancer in the pelvis
* Any psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule; those conditions should be discussed with the patient before inclusion in the trial