In this study we are comparing two forms of radiotherapy. This study is being done because it is not clear at present time whether intensity modulated radiotherapy (IMRT) can reduce side effects of radiotherapy compared to standard radiotherapy (called 3D-Conformal Radiotherapy).

Radical radiation therapy plays an important role in the management of prostate cancer, yielding comparable long-term outcomes to surgery. Unfortunately, long term disease free survival data using PSA criteria have shown that less than 50% of high-risk patients are free of disease at 10 years. To improve on the results of conventional dose radiotherapy dose escalation with three-dimensional conformal radiation has been employed. Due to the irregular shape of the prostate and the variable motion of this organ there is substantial radiation of adjacent normal surrounding tissue during treatment which results in radiation-induced toxicity. Intensity-modulated radiation therapy (IMRT) is a new form of radiation therapy. Preliminary evidence suggests that IMRT improves the dose distribution during radiation therapy of the prostate. The hypothesis of this study is that IMRT delivered using Helical Tomotherapy can reduce late toxicity of radical radiotherapy as compared to three-dimensional conformal radiation (3DCRT) in high-risk prostate cancer patients.

Inclusion Criteria:

1. A pathologic diagnosis of adenocarcinoma of the prostate

2. Age greater than 18 years

3. ECOG performance status of 2 or less.

4. Presence of any of the following high risk features:

   • Clinical stage cT3-4 or
   • Gleason score 8-10 or
   • Pre-treatment PSA > 20ng/ml or
   • Clinical N1/N2 or pathologic N1/N2

Exclusion Criteria:

1. Patients with contraindication to radical radiation therapy including inflammatory bowel disease
2. Prior or active malignancy except non-melanoma skin carcinoma within 5 years of the diagnosis of prostate cancer
3. Prior pelvic radiotherapy for other malignancies
4. Prior cytotoxic chemotherapy
5. Prior orchiectomy, radical prostatectomy, cryotherapy or thermal ablation therapy for prostate cancer