News | Radiation Therapy | February 17, 2017

CyberKnife System Provides Long-term Disease Control for Prostate Cancer Patients

Prospective, multi-institutional study shows CyberKnife SBRT treatment results in low PSA nadir for low- and intermediate-risk prostate cancer patients

Accuray, CyberKnife system, SBRT, long-term disease control, prostate cancer, ASCO GU study

February 17, 2017 — Accuray Inc. recently announced data from a prospective, Phase II, 17-center study which showed that treatment with the CyberKnife System for low- and intermediate-risk prostate cancer provides excellent long-term results. At five years, the disease-free survival rate for low-risk prostate cancer patients was 100 percent and for intermediate-risk patients was 88.5 percent. These results were maintained by patients followed for seven years.

The study was presented at the American Society of Clinical Oncology Genitourinary Cancers Symposium (ASCO GU) Feb. 16-18, 2017, in Orlando, Fla.

A low prostate-specific antigen (PSA) value is associated with a reduced risk of cancer recurrence or metastases. The lower the PSA value and the longer it continues to decline, the greater the patient's likelihood of achieving long-term disease free survival1. According to the study, the five-year median PSA was 0.1 ng/mL for low- and intermediate-risk prostate cancer patients receiving stereotactic body radiation therapy (SBRT) administered with the CyberKnife System. The median PSA value subsequently decreased to 0.035 ng/mL at the seven-year mark for patients followed to this time point.

All patients participating in the study were treated with the CyberKnife System. 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.

Unique aspects of this study included:

  • A highly effective pattern of radiation could be delivered easily by any CyberKnife user as a routine part of their practice — such plans require steep dose fall-off from high-dose regions to rectum, and would be difficult to deliver safely without continual image-guidance and automatic correction of beam aim;
  • Treatment resulted in among the lowest PSA levels reached after radiation therapy (PSA nadirs); and
  • The entire treatment was completed in four days.

The CyberKnife System was designed to deliver SBRT, a treatment process enabling the delivery of radiation throughout the body with an extremely high degree of precision. The system's ability to continually track and automatically correct for movement of the prostate in real-time throughout the entire treatment session provides distinct advantages when treating a tumor which can move as much as 10 mm in as little as 30 seconds2.

"Outcomes from this long-term, prospective study reinforce that CyberKnife prostate SBRT is highly effective, with typically minimal side effects and impact on quality of life during and after treatment," said Donald B. Fuller, M.D., at Genesis Healthcare Partners in San Diego, and lead investigator of the study. "It is important to note that nearly 90 percent of patients in the study were treated at community facilities across the United States, which may provide reassurance for men with localized prostate cancer that the results are achievable in their community setting."

The study 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 five-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.

For more information: www.accuray.com

References

1. Anwar M, et al. Hypofractionated sbrt versus conventionally fractionated ebrt for prostate cancer: Comparison of psa slope and nadir. Radiation oncology 2014;9:42.

2. Kupelian P, et al. Multi-Institutional Clinical Experience with the Calypso System in Localization and Continuous, Real-Time Monitoring of the Prostate Gland During External Radiotherapy. Int J Radiat Oncol Biol Phys. 2007; 67(4):1088–1098. 3. https://www.cancer.gov/types/prostate/prostate-hormone-therapy-fact-shee.... Accessed 2/15/2017.

Related Content

Stronger Distribution Networks to Bolster Radiotherapy Patient Positioning Accessories
News | Patient Positioning Radiation Therapy | July 19, 2019
A recent study projects global market revenues for radiotherapy patient positioning accessories will exceed revenues of...
IBM collected a dataset of 52,936 images from 13,234 women who underwent at least one mammogram between 2013 and 2017.

IBM collected a dataset of 52,936 images from 13,234 women who underwent at least one mammogram between 2013 and 2017, and who had health records for at least one year prior to the mammogram. The algorithm was trained on 9,611 mammograms. Image courtesy of Radiology.

Feature | Artificial Intelligence | July 19, 2019 | Michal Chorev
Breast cancer is the global leading cause of cancer-related deaths in women, and the most commonly diagnosed cancer...
CMS Proposes New Alternative Payment Model for Radiation Oncology
News | Radiation Oncology | July 17, 2019
The Centers for Medicare and Medicaid Services (CMS) issued a proposal for an advanced alternative payment model (APM)...
AAPM 2019 Features More Than 40 Presentations on ViewRay's MRIdian MRI-guided Radiotherapy
News | Image Guided Radiation Therapy (IGRT) | July 16, 2019
ViewRay Inc. announced that the company's MRIdian System is the focus of more than 40 abstracts selected by the...
RaySearch Releases Version 3A of RayCare Oncology Information System
Technology | Oncology Information Management Systems (OIMS) | July 15, 2019
RaySearch has released RayCare 3A, a new version of the next-generation oncology information system (OIS). RayCare is...
IBA Launches Monte Carlo Patient QA for Varian Halcyon at AAPM 2019
Technology | Quality Assurance (QA) | July 10, 2019
IBA announced the launch of the latest functionality of the SciMoCa Monte Carlo Patient QA solution at the 61st annual...
Researchers Use Artificial Intelligence to Deliver Personalized Radiation Therapy
News | Radiation Therapy | July 09, 2019
New Cleveland Clinic-led research shows that artificial intelligence (AI) can use medical scans and health records to...
The Beamscan 3-D water phantom with the Varian Halcyon radiotherapy system

The Beamscan 3-D water phantom with the Varian Halcyon radiotherapy system. Image courtesy of PTW.

News | Quality Assurance (QA) | July 08, 2019
At this year’s American Association of Physicists in Medicine (AAPM) show, July 14-18 in San Antonio, Texas, PTW will...
Aktina Medical Partners With Elekta for Global Distribution of Interlocking SRS Cones
News | Radiation Therapy | July 05, 2019
Aktina Medical announced that Elekta Instrument AB, based in Sweden, will offer and distribute the Aktina line of...