Health Technology Brief

supporting sound, evidence-based decision making

Stereotactic Body Radiation Therapy with CyberKnife Robotic Radiosurgery System (Accuray Inc.) Boost Treatment in Primary Localized Prostate Cancer

October 20, 2016

Prostate cancer is expected to be the most common cancer diagnosed among men in the United States in 2016, comprising nearly 180,890 new cases with a projected 26,120 deaths. In contrast to patients with lower-risk disease, those with locally confined high-risk prostate cancer and those with intermediate-risk disease with 2 or more risk factors typically have poorer prognoses requiring more intensified treatment. High-dose-rate (HDR) brachytherapy is commonly used as a “boost” to conventionally fractionated external beam radiation therapy (EBRT) in this setting, but is highly invasive and resource-intensive. Extreme hypofractionated stereotactic body radiation therapy (SBRT) is emerging as a noninvasive alternative to HDR brachytherapy as a boost.

Description of Technology: This health technology assessment focuses on the use of the CyberKnife SBRT platform to deliver boost therapy in men who have intermediate- to high-risk, localized prostate cancer. Boost treatment with CyberKnife is intended to recapitulate radiation delivery doses and distribution profiles similar to those possible with HDR brachytherapy when used to boost standard EBRT dosage. It does not require anesthetic, placement of intraprostatic catheters, or inpatient hospitalization. Gold fiducials are placed within the prostate to help identify and track the location of the gland and tumor. A treatment plan is developed based on a high-resolution computed tomography imaging study fused with a magnetic resonance image study to outline the prostate gland and fiducials. The CyberKnife computer-controlled robot slowly moves around the patient to deliver radiation from 150 to 300 angles. Five or fewer treatments, each lasting 30 to 90 minutes, are required.

Patient Population: CyberKnife has been used in patients with previously untreated, localized prostate cancer, and in previously treated patients with advanced or recurrent prostate cancer. The patient population under consideration in this health technology assessment include treatment-naïve men with intermediate- to high-risk localized prostate cancer who receive definitive therapy with EBRT plus CyberKnife SBRT boost.

Clinical Alternatives: Prostate cancer treatment is guided by the initial disease risk category. Options can include active surveillance or watchful waiting; radical prostatectomy; EBRT using 3-dimensional conformal radiation therapy or intensity-modulated radiotherapy; HDR brachytherapy; high-intensity-focused ultrasound; hormonal therapy; cryosurgery; or combinations thereof.