CyberKnife® System Provides Effective Treatment Option with Minimal Side Effects and Excellent Cosmesis for Early Stage Breast Cancer Patients

Accuray Incorporated (NASDAQ: ARAY) announced today preliminary results from a prospective, phase I clinical trial evaluating adjuvant stereotactic partial breast irradiation (S-PBI) in early stage breast cancer patients treated with the CyberKnife® System. The study, published in the May issue of the peer-reviewed International Journal of Radiation Oncology - Biology - Physics, reported no recurrences or distant metastases at median follow-up of 26 months. Additionally, at two years, more than 95 percent of patients and 100 percent of physicians rated cosmesis as excellent or good, indicating both patients and physicians were satisfied with the appearance of the breast (cosmesis) following treatment.

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For further information on the CyberKnife System, visit http://www.accuray.com/product/cyberknife

"The results of this phase 1 study highlight a new approach for treating breast cancer while minimizing tissue exposure. We believe our protocol offers reproducible and executable guidance for other radiation therapy teams interested in incorporating S-PBI into their practice," said Asal Rahimi, M.D., M.S., Assistant Professor of Radiation Oncology, University of Texas Southwestern Medical Center, in Dallas, Texas. "Our study shows the benefits of real-time image guidance and motion control when delivering S-PBI."

The study titled, "Preliminary Results of a Phase 1 Dose Escalation Trial for Early Stage Breast Cancer Using 5-Fraction Stereotactic Body Radiation Therapy for Partial Breast Irradiation (S-PBI)," provides results for 75 patients treated with S-PBI following lumpectomy. It showed:

• Real-time image guidance and motion control with the Synchrony® Respiratory Tracking System enabled precise treatments, ultimately limiting toxicity and preserving cosmesis;
• Dose escalation to 40 Gy/5 fractions is possible without exceeding the maximum tolerated dose. Treatments provided tumor control with minimal acute or late side effects;
• S-PBI provides a more convenient treatment option than hypofractionated whole-breast irradiation (NCCN guideline: 40-42.5 Gy over 15-16 fractions), with no compromise in tolerability or short-term efficacy.

"Numerous clinical studies have shown the benefit of breast conservation therapy, consisting of lumpectomy and radiation, for increasing long-term survival. With advances in radiation therapy technologies, clinicians continue to evaluate protocols to determine the best treatment approach," said Fabienne Hirigoyenberry-Lanson, PhD, Vice President Global Medical and Scientific Affairs, at Accuray. "This study indicates S-PBI could become an important option in the treatment of women with early-stage breast cancer. The CyberKnife System is a non-invasive option delivered in a reduced number of treatments, which may provide an optimal combination of efficacy, tolerability and convenience for many patients."

The CyberKnife System enables precise dose distributions to be confidently delivered to the patient with extreme accuracy over a minimum number of treatments, reducing side effects and preserving patients' quality of life. Unlike any other radiation delivery system, the CyberKnife® technology continually tracks and automatically adjusts the beam for movement in real-time, as the patient breathes normally, throughout the entire treatment session. The system's sub-millimeter accuracy enhances clinicians' abilities to treat effectively while preserving healthy tissue.

Said Joshua H. Levine, President and CEO of Accuray, "This study shows the benefits of hypofractionated doses delivered with the CyberKnife System in women with early-stage breast cancer: a short course of treatment that is effective with minimal side effects."

About the Phase I Trial 

The purpose of this prospective, phase I study was to evaluate the maximum tolerated dose (MDT) of five fraction stereotactic body radiation therapy for partial breast irradiation (S-PBI) in treating early stage-breast cancer after lumpectomy. All patients were treated with the CyberKnife System which delivers non-isocentric and non-coplanar radiation beams. Patient follow-up occurred every three months for year 1 and every six months until year 5. Longer follow-up and additional Phase II/III data are required to follow late toxicities, control, and determination of the optimal dose to be considered for standard use.

Important Safety Information 

For Important Safety Information please refer to http://www.accuray.com/safety-statement-radiation-treatment

About Accuray 

Accuray Incorporated (Nasdaq: ARAY) is a radiation oncology company that develops, manufactures and sells precise, innovative treatment solutions that set the standard of care with the aim of helping patients live longer, better lives.  The company's leading-edge technologies deliver the full range of radiation therapy and radiosurgery treatments. For more information, please visit http://www.accuray.com.

Safe Harbor Statement 

Statements made in this press release that are not statements of historical fact are forward-looking statements and are subject to the "safe harbor" provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements in this press release relate, but are not limited, to clinical applications, clinical results, patient outcomes and Accuray's leadership position in radiation oncology innovation and technologies. Forward-looking statements are subject to risks and uncertainties that could cause actual results to differ materially from expectations, including but not limited to the risks detailed from time to time under the heading "Risk Factors" in the company's report on Form 10-K, filed on August 24, 2016, the company's reports on Form 10-Q, filed on November 1, 2016 and February 3, 2017, and as updated periodically with the company's other filings with the SEC.

Forward-looking statements speak only as of the date the statements are made and are based on information available to the company at the time those statements are made and/or management's good faith belief as of that time with respect to future events.  The company assumes no obligation to update forward-looking statements to reflect actual performance or results, changes in assumptions or changes in other factors affecting forward-looking information, except to the extent required by applicable securities laws.  Accordingly, investors should not put undue reliance on any forward-looking statements.