Intensity Modulated Radiation Therapy - Prostate Cancer

Inclusion Criteria: * Histologic diagnosis of adenocarcinoma of the prostate within six months of entry * Clinical stage T1B, T1C, T2A-C NX MO (see Appendix 1 for staging). Any Gleason score is eligible for entry, but Gleason score must be determined. * Patients with a PSA \>10.0 and Gleason score of 7; or patients with any PSA value and Gleason score of \>8 must have clinically negative lymph nodes as determined by a pelvic CT scan done within 12 weeks of entry. A negative bone scan is required before entry for all patients with Gleason score \>8, or any patient with a Gleason score of 7, and a PSA \>10. * The patient must not have received any cytotoxic anticancer therapy. Previous or concurrent hormonal therapy for local disease is acceptable. * ECOG performance status of 1 or less * Age 80 years old or less * Serum PSA \<25 ng/ml within 4 weeks of study entry * Informed consent Exclusion Criteria: * Patients with history of inflammatory bowel disease or other contraindication to radical radiation therapy * Patients with prior colorectal surgery * Any prior pelvic radiotherapy. Any prior TURP done \<12 weeks from study entry. * Any previous cytotoxic chemotherapy * Patients with prior malignancy except non-melanoma skin carcinoma within 5 years of the diagnosis of prostate cancer