Radiotherapy to the Prostate and Dominant Intra-Prostatic Lesion (DIL)

Inclusion Criteria:

Intermediate risk prostate cancer patients will be eligible for this study. Risk groups will be assigned as per NCCN guidelines. Intermediate risk patients will be defined as:

PSA 10-20 ng/ml or
Gleason score = 7 or
Clinical stage T2b/T2c

Additionally, patients will be required to meet the following criteria:

Age >18
KPS > 80
Prostate size < 60cc
Presence of a prostatic lesion with maximum dimension of >/= 0.5cm and no more than two additional disease foci, each with a maximum dimension less than that of the dominant lesion.
International Prostrate Symptom Score < 15
Subjects must fill out the standard MRI screening form and satisfy all MRI screening criteria

Exclusion Criteria:

Prior androgen deprivation therapy for prostate cancer
Evidence of metastatic disease on bone scan or MRI/CT
MRI ineligibility due to the presence of a cardiac pacemaker, defibrillator or other implanted metallic or electronic device which is considered MR unsafe, severe claustrophobia or inability to lie flat for the duration of the study, etc.
Metallic hip implant, metallic implant or device in the pelvis that might distort the local magnetic field and compromise quality of MP-MRI.
Lateral pelvic separation greater than 50 cm and/or anterior-posterior separation greater than 35 cm which are incompatible with MRCAT reconstruction
Contra-indications to receiving gadolinium contrast
KPS < 80
Pelvic MRI or CT (MRI preferred) evidence of radiographic T3, T4 or N1 disease.
Prior history of transurethral resection of the prostate
Prior history of chronic prostatitis
Prior history of urethral stricture
Prior history of pelvic irradiation
History of inflammatory bowel disease
Unable to give informed consent
Unable to complete quality of life questionnaires

Abnormal complete blood count. Any of the following

Platelet count less than 75,000/ml
Hb level less than 10 gm/dl
WBC less than 3.5/ml
Abnormal renal function tests (creatinine > 1.5)