SUNNYVALE, Calif., Sept. 25, 2018 /PRNewswire/ -- Accuray Incorporated (NASDAQ :ARAY ) announced today that published data from two prospective, multi-center studies using differing protocols provide consistent results and reinforce the use of the CyberKnife® System for the effective management of low- and intermediate-risk prostate cancer. These studies are the largest conducted to date evaluating stereotactic body radiation therapy (SBRT) in patients with localized prostate cancer. The studies were recently published online in the International Journal of Radiation Oncology*Biology*Physics and in the European Urology Oncology.
The CyberKnife System delivers radiation with sub-millimeter precision, enhancing clinicians' ability to treat effectively while preserving healthy tissue. In addition to clinical benefits, SBRT is more convenient for patients and has been shown to be less costly than long courses of intensity-modulated radiation therapy (IMRT).
Growing clinical evidence suggests that dose-escalation may translate to improved clinical outcomes for prostate cancer. Research suggests that, unlike most tumors, prostate cancer cells are highly sensitive to the amount of radiation dose delivered per fraction or treatment session. In recent years, this has led clinicians to consider hypo-fractionated schedules—the delivery of a higher dose per fraction in fewer fractions than conventional schedules—with promising results. SBRT, which combines a high degree of targeting accuracy with very high doses of extremely precise, externally-delivered radiation over four to five sessions, provides an option for accomplishing this goal.
Highlights of the Multi-Center Studies
Pinpoint precision results in exceptional survival rates
Prostate SBRT administered by the system resulted in the following disease-free survival rates:
97% - 100% for low-risk patients
Superior to the 92% - 94% from conventional radiation therapy historic data
Equivalent to low dose rate (LDR) brachytherapy and high dose rate (HDR) brachytherapy without the inconvenience and risk associated with invasive seed and catheter implants
88% - 97% for intermediate-risk patients
Equal to or higher than the 85% - 90% reported with conventional radiation therapy without the inconvenience of daily visits over several weeks
Minimal toxicity even with high radiation dose
Despite the high dose delivered to the prostate, side effects were uncommon (less than two percent grade 3 or higher toxicities) and were similar to other radiation therapy procedures without the need for invasive rectal balloons or spacers to spare the rectal wall.
