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

Prospective Evaluation of CyberKnife Stereotactic Radiosurgery for Low and 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.

In this study, CyberKnife radiosurgery will be used to produce dose distributions comparable to those created by High Dose Rate (HDR) brachytherapy treatment, without the use of invasive catheters. The radiosurgery volumes will closely be made to resemble HDR brachytherapy therapeutic volumes with similar dose limitation objectives to adjacent normal tissues.

The CyberKnife Robotic Radiosurgery System is a unique radiosurgical system capable of treating tumors anywhere in the body noninvasively and with sub-millimeter accuracy. The CyberKnife System delivers radiation using a precise targeting methodology allowing a focal treatment margin around the target, thus limiting the volume of adjacent tissue receiving high doses radiation. This in turn allows the delivery of high doses of radiation to the prostate over a short series of treatments.

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