Additional Study Outcomes

The study, "Five-Year Outcomes from a Prospective Multi-Institutional Trial of Heterogeneous Dosing Stereotactic Body Radiotherapy (SBRT) for Low- and Intermediate-Risk Prostate Cancer," evaluated a dosing regimen which emulated a high-dose brachytherapy (HDR) plan. It demonstrated that:


Patients experienced low toxicity rates despite the high SBRT dosage and heterogeneous dose distribution specific to this study, with higher dosage in the prostate peripheral zone;
The 5-year local and distant failure-free remission rates (98.3 percent and 97.3 percent, respectively), for the entire patient population, were achieved with the CyberKnife System alone. This enables patients to avoid the unfortunate side effects associated with the use of androgen deprivation therapy (aka "hormone therapy") including loss of libido, hot flashes, bone fractures and weight gain3; and
The results were obtained without the need for invasive rectal balloons or spacers to spare the rectal wall.

"This is the second large, prospective, multi-institutional study to bring clinical evidence of the benefits of CyberKnife SBRT for the treatment of patients with low- to intermediate-risk prostate cancer. No other radiation therapy device for prostate SBRT is supported by such a robust clinical database," said Fabienne Hirigoyenberry-Lanson, PhD, vice president global clinical development, at Accuray. "These data show why CyberKnife prostate SBRT is increasingly being viewed as the treatment of choice by clinicians and patients who want a non-invasive option that provides excellent disease control with minimal side effects."

Details of a previously presented multi-institutional study titled, "Prospective Evaluation of CyberKnife Stereotactic Radiosurgery for Low- and Intermediate-Risk Prostate Cancer: Homogenous Dose Distribution," which showed that five treatments with the CyberKnife System provided excellent disease control for prostate cancer patients, can be found at http://www.accuray.com/pressroom/press-releases/prospective-multi-institutional-study-shows-five-treatments-cyberknife. The study was presented at the American Society for Radiation Oncology (ASTRO) 58th Annual Meeting and the 2016 Best of ASTRO meeting.


About the Heterogeneous Dosing SBRT Study
Seventeen institutions analyzed 259 prostate cancer patients; 112 low-risk and 147 intermediate-risk. Patients received an HDR-like heterogeneous dosing regimen of 38 Gy/four fractions delivered by the CyberKnife System. The primary study objectives were to determine biochemical disease free survival (bDFS) and measure the rates of acute and late genitourinary and gastrointestinal toxicities following treatment, and to compare the CyberKnife System bDFS rates to published HDR brachytherapy bDFS rates reported in the literature.

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