SUNNYVALE, Calif., Feb. 16, 2023 /PRNewswire/ -- Accuray Incorporated (NASDAQ: ARAY) announced today that data from the randomized, multicenter trial PACE-A (PACE - Prostate Advances in Comparative Evidence) indicates that stereotactic body radiation therapy (SBRT), in comparison to surgery, better preserves urinary continence and sexual function in men with localized prostate cancer. The study, which was led by The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research, London, is being presented during an oral session at the American Society of Clinical Oncology Genitourinary Cancers Symposium (ASCO GU) in San Francisco, California.

123 men from 10 UK centers were enrolled in the trial, with 59 ultimately treated with SBRT and 50 with surgery. An analysis of patient reported outcomes found that at two years, significantly fewer patients (4.5%) treated with SBRT reported needing to use urinary pads, which manage urinary incontinence, compared with surgery (47%)¹. Patients treated with SBRT also reported better sexual function after two years than those treated with surgery².

While moderate or serious bowel problems were not reported by many men in the study, those treated with SBRT were more likely (16%) than surgical patients to report minor problems (0%)³.

SBRT is a highly targeted form of external beam radiation therapy that involves the delivery of very high doses of radiation over a small number of treatment sessions, offering convenience for patients. The delivery of radiation is an outpatient, non-invasive procedure that does not require general anesthesia and most patients will not require a long recovery period. In the PACE-A trial patients were treated with SBRT delivered in 5 sessions over 1-2 weeks or surgery, either laparoscopic or robotically assisted prostatectomy.

Professor Nicholas van As, M.D., Medical Director and Consultant Clinical Oncologist of The Royal Marsden NHS Foundation Trust and Professor in Precision Prostate Radiotherapy at The Institute of Cancer Research, London and lead investigator of the trial, said:

"This world-first study reveals that SBRT, an advanced form of radiotherapy now widely available across the UK, is often kinder and can mean less long-term side effects than surgery for prostate cancer patients.

"One of the biggest concerns for men I see in clinic ahead of treatment for prostate cancer is whether it will make them incontinent, and many worry about the impact on their sexual function too. While there is a risk both SBRT and surgery will cause problems, these results suggest SBRT is less likely to.

"Going forwards, these results should support clinicians in facilitating important discussions with prostate cancer patients about whether to opt for SBRT or surgery, helping them make an informed decision based on their individual needs and concerns." 

The CyberKnife^® System, designed to deliver SBRT, features a linear accelerator mounted to a robotic arm that aims radiation beams from potentially thousands of unique angles, targeting only the tumor while minimizing radiation dose to healthy tissue. The system's accuracy is sub-millimeter, meaning its pinpoint precision is less than the thickness of a coin, even as the prostate moves unpredictably. The CyberKnife System uses the Accuray-proprietary artificial intelligence (AI)-driven Synchrony^® technology to detect when the prostate moves and synchronizes the treatment delivery beam to the random movement of the prostate in real-time throughout the entire treatment session.

Seth Blacksburg, M.D., MBA, Vice President and Chief Medical Officer Americas region at Accuray said, "Men undergoing treatment for prostate cancer want a highly accurate, effective, and efficient treatment that allows them to get back to their daily lives with minimal-if-any impact on long-term urinary, rectal, and sexual function. The results of the PACE-A study support and expand upon previous important investigations—such as the ProtecT trial published in the New England Journal of Medicine in 2016—and indicate that SBRT can do just that.

Dr. Blacksburg continued, "A large body of evidence highlights the versatility of the CyberKnife^® platform to effectively deliver SBRT to cure prostate cancer. The system's ability to deliver extremely precise and accurate treatment to a moving target allows physicians and patients alike to feel confident that cancers at various stages of disease are addressed with minimal impact on normal tissue."

About the PACE-A Trial

PACE-A, a randomized controlled trial comparing SBRT to surgery - laparoscopic or robotically assisted prostatectomy - for localized prostate cancer, represents one study of a three-study trial platform. It is sponsored by The Royal Marsden and managed by The Clinical Trials and Statistics Unit at The Institute of Cancer Research (ICR). Of the 123 patients enrolled by 10 United Kingdom centers participating in the PACE-A trial, 109 patients received treatment; 59 receiving SBRT and 50 surgery. Androgen deprivation was not permitted. The trial evaluated the treatment regimens across quality-of-life measures that were presented at ASCO GU.

Toxicity results from PACE-B, comparing SBRT to conventionally fractionated or moderately hypofractionated external beam radiotherapy (CFMHRT) for localized prostate cancer, has been published in The Lancet Oncology. Five year efficacy outcomes for PACE-B (the primary outcome measure) should be available later this year. Outcomes of the PACE-C trial, comparing hypofractionated SBRT to conventionally fractionated or moderately hypofractionated external beam radiotherapy (CFMHRT) in intermediate and high-risk patients requiring 6 months of hormone therapy, will be shared when available. PACE-C closed to recruitment in June 2022.

All three of the PACE studies are sponsored by The Royal Marsden NHS Foundation Trust and coordinated by the Clinical Trials and Statistics Unit at the ICR. PACE-A is funded by Accuray and Varian, a Siemens Healthineers company, PACE-B is funded by Accuray and endorsed by Cancer Research UK, and PACE-C is funded by The Royal Marsden Cancer Charity.

About Accuray

Accuray is committed to expanding the powerful potential of radiation therapy to improve as many lives as possible. We invent unique, market-changing solutions designed to deliver radiation treatments for even the most complex cases—while making commonly treatable cases even easier—to meet the full spectrum of patient needs. We are dedicated to continuous innovation in radiation therapy for oncology, neuro-radiosurgery, and beyond, as we partner with clinicians and administrators, empowering them to help patients get back to their lives, faster. Accuray is headquartered in Sunnyvale, California, with facilities worldwide. To learn more, visit www.accuray.com or follow us on Facebook, LinkedIn, Twitter, and YouTube.

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¹ At two years, 44 of those treated with SBRT and 32 of those treated with surgery responded to this query, with two of the SBRT cohort and 15 of the surgical group reporting the use of urinary pads.
² The Expanded Prostate Cancer Index-Short Form (EPIC-26) questionnaire, which is used for measuring health-related of life, was applied here. At 2 years, 41 SBRT patients reported an EPIC sexual subdomain score with mean of 58, compared with 30 surgical patients who reported a mean score of 29.3.
³ At two years, 46 of those treated with SBRT and 31of those treated with surgery responded to this query, with 7 of the SBRT cohort reporting a moderate/serious problem with bowel symptoms and none of the surgical cohort reporting problems.