CyberKnife Radiosurgery For Low & Intermediate Risk Prostate Cancer: Emulating HDR Brachytherapy Dosimetry

The purpose of this study is to investigate the effects of CyberKnife radiosurgery in patients with early stage organ-confined prostate cancer and to evaluate the effects of this treatment on the quality of life over time.

Inclusion Criteria: * Patient must be at least 18 years of age * Histologically proven prostate adenocarcinoma * Biopsy within 1 year of date of registration * Clinical Stage (CS) T1b-T2b, N0, M0 * Patients belonging to one of the following risk categories: * Low Risk: CS T1b-T2a, Gleason Score 2-6, Prostate Specific Antigen (PSA) \< or = 10 ng/ml * Intermediate Risk: CS T2b, Gleason Score 2-6, PSA \< or = 10 ng/ml or CS T1b-T2b, Gleason Score 2-6, PSA \< or = 20 ng/ml or CS T1b-T2b, Gleason Score 7 and PSA \< or = 10 ng/ml * Eastern Cooperative Oncology Group (ECOG) performance status 0-1 Exclusion Criteria: * Clinical Stage T2c or greater * Prior prostatectomy or cryotherapy of the prostate * Prior radiotherapy of the prostate or lower pelvis * Implanted hardware or other material that would prohibit appropriate treatment planning or delivery * History of an invasive malignancy other than basal or squamous skin cancers in the last 5 years * Hormone ablation for two months prior to enrollment or during treatment