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

MIM Software Inc. Receives FDA 510(k) Clearance for Molecular Radiotherapy Dosimetry
Technology | Nuclear Imaging | January 16, 2019
MIM Software Inc. received 510(k) clearance from the U.S. Food and Drug Administration (FDA) for molecular radiotherapy...
Artificial Intelligence Used in Clinical Practice to Measure Breast Density
News | Artificial Intelligence | January 15, 2019
An artificial intelligence (AI) algorithm measures breast density at the level of an experienced mammographer,...
Machine Learning Uncovers New Insights Into Human Brain Through fMRI
News | Neuro Imaging | January 11, 2019
An interdisciplinary research team led by scientists from the National University of Singapore (NUS) has successfully...
Mobile App Data Collection Shows Promise for Population Health Surveys
News | Population Health | January 10, 2019
Mobile app data collection can bring access to more potential clinical study participants, reduce clinical study...
Hypertension With Progressive Cerebral Small Vessel Disease Increases Cognitive Impairment Risk
News | Magnetic Resonance Imaging (MRI) | January 08, 2019
Patients with high blood pressure and progression of periventricular white matter hyperintensities showed signs of...
Artificial Intelligence Pinpoints Nine Different Abnormalities in Head Scans

A brain scan (left) showing an intraparenchymal hemorrhage in left frontal region and a scan (right) of a subarachnoid hemorrhage in the left parietal region. Both conditions were accurately detected by the Qure.ai tool. Image courtesy of Nature Medicine.

News | Artificial Intelligence | January 07, 2019
The rise in the use of computed tomography (CT) scans in U.S. emergency rooms has been a well-documented trend1 in...
Electronic Brachytherapy Effective in Long-Term Study of 1,000 Early-Stage Breast Cancers
News | Brachytherapy Systems, Women's Healthcare | January 07, 2019
Breast cancer recurrence rates of patients treated with intraoperative radiation therapy (IORT) using the Xoft Axxent...
Brachytherapy Alone Superior Treatment for Intermediate-Risk Prostate Cancer
News | Brachytherapy Systems | January 04, 2019
Patient-reported outcomes (PROs) indicated a significantly different clinician and patient-reported late toxicity...
Breast Cancer Patients Have Less Heart Damage With Heart Drug and Trastuzumab
News | Cardio-oncology | January 03, 2019
Breast cancer patients who take a heart drug at the same time as trastuzumab have less heart damage, according to a...
MRI Effective for Monitoring Liver Fat in Obese Patients
News | Magnetic Resonance Imaging (MRI) | December 28, 2018
Magnetic resonance imaging (MRI) provides a safe, noninvasive way to monitor liver fat levels in people who undergo...