A Phase II Study of Stereotactic Body Radiotherapy (SBRT) for Prostate Cancer Using Continuous Real-time Evaluation of Prostate Motion and IMRT Plan Reoptimization Based on the Anatomy of the Day

Inclusion Criteria:

- Histologically confirmed diagnosis of adenocarcinoma of the prostate within 365 days
of study enrollment

- History/physical examination with digital rectal examination of the prostate within 8
weeks prior to study enrollment

- Gleason score less than or equal to 7

- Clinical Stage T1-T2c

- PSA

- less than or = 15 ng/ml prior to start of therapy if Gleason < or = 6 or

- less than or = 10 ng/ml prior to start of therapy if Gleason = 7

- Zubrod Performance Status 0-1

- Age > 40

Exclusion Criteria:

- Prior or concurrent invasive malignancy (except non-melanomatous skin cancer) or
lymphomatous/hematogenous malignancy unless continually disease free for a minimum of
5 years. (Carcinoma in situ of the bladder or oral cavity is permissible)

- Evidence of distant metastases

- Regional lymph node involvement

- Significant urinary obstruction

- Estimated prostate gland > 100 grams

- Previous radical surgery (prostatectomy) or cryosurgery for prostate cancer

- Previous pelvic irradiation, prostate brachytherapy, or bilateral orchiectomy

- Previous hormonal therapy, such as LHRH agonists (e.g. goserelin, leuprolide),
anti-androgens (e.g., flutamide, bicalutamide), estrogens (e.g., DES), or surgical
castration (bilateral orchiectomy) or planned concurrent androgen deprivation therapy

- Previous or concurrent cytotoxic chemotherapy for prostate cancer

- Prosthetic implants in the pelvic region that contain metal or conductive materials
(e.g., an artificial hip).

- Severe, active comorbidity