18 and older, male only, with Prostate Cancer or Prostatic Cancer. Patients with the condition only — healthy volunteers not accepted.
Results — posted to ClinicalTrials.gov
Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.
Risk for Gastrointestinal (GI) and Genitourinary (GU) ToxicityPrimary· Primary Safety Endpoint was measured at 5 years. Sites and patients had the option of continuing follow-up through 10 years.
To estimate the rates of acute and late Grade 3-5 gastrointestinal and genitourinary toxicities (adverse events \[AE\]) observed in both low-risk and intermediate-risk cohorts during the 5 years following CyberKnife (CK) treatment for prostate cancer. Kaplan Meier estimates for 5-yr and 10-yr are reported.
Adverse events occurring within 3 months of treatment were categorized as acute toxicities, and those developing after 3 months were considered late toxicities.
The rates were determined using the first Grade 3 or higher adverse event per patient, reported as possibly, probably, or definit
Probability of experiencing Acute GI Grade 3+ event(s)
Group
Value
95% CI
Low Risk
0
Intermediate Risk
0
Probability of experiencing Acute GU Grade 3+ event(s)
Group
Value
95% CI
Low Risk
1.8
Intermediate Risk
0.7
Probability of experiencing Late GI Grade 3+ events 5 years post treatment
Group
Value
95% CI
Low Risk
0
Intermediate Risk
0
Probability of experiencing Late GU Grade 3+ events 5 years post treatment
Group
Value
95% CI
Low Risk
1.0
Intermediate Risk
3.7
Probability of experiencing Late GI Grade 3+ event(s) at 10 years post CK treatment
Group
Value
95% CI
Low Risk
0
Intermediate Risk
0
Probability of experiencing Late GU Grade 3+ event(s) at 10 years post CK treatment
Group
Value
95% CI
Low Risk
1.0
Intermediate Risk
3.7
Biochemical Disease-Free Survival (bDFS)Primary· Primary Efficacy Endpoint was measured at 5 years. Sites and patients had the option of continuing follow-up through 10 years.
To determine the rate of biochemical Disease-Free Survival (bDFS), using the Phoenix definition, following CyberKnife treatment. Kaplan Meier survival curves for bDFS were created and the 5-yr and 10-yr percentages are reported.
The Phoenix definition uses a Prostate Specific Antigen (PSA) value exceeding the patients lowest PSA value (nadir) + 2 ng/mL as an indicator of disease recurrence. The percentage of patients who did not have such a PSA rise or receive any interventional therapy to treat prostate cancer are reported below.
Probability of remaining disease-free at 5 years post-CyberKnife treatment
Group
Value
95% CI
Low Risk
100
Intermediate Risk
89.1
Probability of remaining disease-free at 10 years post-CyberKnife treatment
Group
Value
95% CI
Low Risk
100
Intermediate Risk
80
Disease Control and Survival OutcomesSecondary· Secondary outcomes were measured at 5 years. Sites and patients had the option of continuing follow-up through 10 years.
To determine the rates of local failure, distant failure, disease-free survival, disease-specific survival, and overall survival following CyberKnife treatment in prostate cancer patients.
Probability of remaining free from Local Failure at 5 years post-CyberKnife treatment
Quality of Life Assessments: American Urological Association (AUA) Symptom Index (SI)Secondary· AUA questionnaire was completed at Baseline, CK Treatment, and post treatment at: 1 week, 1 month, 3 months, 6 months, and then biannually up to 5 years. Sites and patients had the option of continuing follow-up through 10 years.
AUA-SI is a 7-item self-report measure used to assess urinary urgency, frequency, and voiding symptoms with scores ranging from 0 (no symptom) to 5 (symptom occurs almost always) Total score: 0-7 mild symptoms; 8-19 moderate symptoms; 20-35 severe symptoms
Quality of Life Assessments: Expanded Prostate Cancer Index Composite (EPIC) -26 Urinary IncontinenceSecondary· Secondary outcomes were measured at 5 years. Sites and patients had the option of continuing follow-up through 10 years.
EPIC-26 is a short form version of the Expanded Prostate Cancer Index Composite, and is a validated comprehensive instrument developed to measure the health-related quality of life among men with prostate cancer. EPIC-26 consists of 26 items under 5 domains of urinary incontinence, urinary irritative/obstructive, bowel, sexual, and hormonal.
Answers qualitatively measure patient's bother for each symptom and are then normalized on a scale of 0 (worst) to 100 (best) to calculate domain scores if sufficient input is provided.
Baseline
Group
Value
95% CI
Low Risk
95.77
± 10.42
Intermediate Risk
91.59
± 14.39
1 Month Post Treatment
Group
Value
95% CI
Low Risk
90.33
± 14.56
Intermediate Risk
88.83
± 16.85
6 Months Post Treatment
Group
Value
95% CI
Low Risk
92.81
± 14.08
Intermediate Risk
88.48
± 16.51
12 Months Post Treatment
Group
Value
95% CI
Low Risk
90.64
± 17.39
Intermediate Risk
85.37
± 19.23
24 Months Post Treatment
Group
Value
95% CI
Low Risk
87.66
± 17.32
Intermediate Risk
78.44
± 25.72
36 Months Post Treatment
Group
Value
95% CI
Low Risk
90.2
± 19.38
Intermediate Risk
81.08
± 22.8
48 Months Post Treatment
Group
Value
95% CI
Low Risk
88.74
± 20.88
Intermediate Risk
80.62
± 22.11
60 Months Post Treatment
Group
Value
95% CI
Low Risk
89.5
± 18.31
Intermediate Risk
80.04
± 20.8
Quality of Life Assessments: EPIC-26 Urinary Irritative ObstructiveSecondary· Secondary outcomes were measured at 5 years. Sites and patients had the option of continuing follow-up through 10 years.
EPIC-26 is a short form version of the Expanded Prostate Cancer Index Composite, and is a validated comprehensive instrument developed to measure the health-related quality of life among men with prostate cancer. EPIC-26 consists of 26 items under 5 domains of urinary incontinence, urinary irritative/obstructive, bowel, sexual, and hormonal.
Answers qualitatively measure patient's bother for each symptom and are then normalized on a scale of 0 (worst) to 100 (best) to calculate domain scores if sufficient input is provided.
Baseline
Group
Value
95% CI
Low Risk
87.67
± 13.96
Intermediate Risk
87.59
± 12.32
1 Month Post Treatment
Group
Value
95% CI
Low Risk
74.11
± 17.49
Intermediate Risk
74.03
± 17.82
6 Months Post Treatment
Group
Value
95% CI
Low Risk
86.75
± 14.69
Intermediate Risk
82.91
± 17.4
12 Months Post Treatment
Group
Value
95% CI
Low Risk
83.29
± 15.45
Intermediate Risk
80.1
± 18.79
24 Months Post Treatment
Group
Value
95% CI
Low Risk
86.56
± 15.09
Intermediate Risk
81.05
± 18.71
36 Months Post Treatment
Group
Value
95% CI
Low Risk
86.99
± 15.09
Intermediate Risk
85.77
± 16.77
48 Months Post Treatment
Group
Value
95% CI
Low Risk
87.81
± 13.03
Intermediate Risk
84.03
± 16.36
60 Months Post Treatment
Group
Value
95% CI
Low Risk
87.72
± 14.9
Intermediate Risk
84.15
± 14.32
Quality of Life Assessments: EPIC-26 BowelSecondary· Secondary outcomes were measured at 5 years. Sites and patients had the option of continuing follow-up through 10 years.
EPIC-26 is a short form version of the Expanded Prostate Cancer Index Composite, and is a validated comprehensive instrument developed to measure the health-related quality of life among men with prostate cancer. EPIC-26 consists of 26 items under 5 domains of urinary incontinence, urinary irritative/obstructive, bowel, sexual, and hormonal.
Answers qualitatively measure patient's bother for each symptom and are then normalized on a scale of 0 (worst) to 100 (best) to calculate domain scores if sufficient input is provided.
Baseline
Group
Value
95% CI
Low Risk
96.25
± 8.14
Intermediate Risk
94.84
± 9.96
1 Month Post Treatment
Group
Value
95% CI
Low Risk
89.32
± 14.63
Intermediate Risk
86.05
± 16.66
6 Months Post Treatment
Group
Value
95% CI
Low Risk
93.45
± 12.06
Intermediate Risk
89.92
± 15.91
12 Months Post Treatment
Group
Value
95% CI
Low Risk
93.51
± 11.41
Intermediate Risk
87.97
± 17.42
24 Months Post Treatment
Group
Value
95% CI
Low Risk
93.68
± 11.16
Intermediate Risk
89.28
± 17.26
36 Months Post Treatment
Group
Value
95% CI
Low Risk
94.82
± 9.27
Intermediate Risk
93.29
± 12.48
48 Months Post Treatment
Group
Value
95% CI
Low Risk
94.65
± 9.77
Intermediate Risk
92.04
± 12.28
60 Months Post Treatment
Group
Value
95% CI
Low Risk
94.49
± 11.67
Intermediate Risk
91.03
± 15.38
Quality of Life Assessments: EPIC-26 SexualSecondary· Secondary outcomes were measured at 5 years. Sites and patients had the option of continuing follow-up through 10 years.
EPIC-26 is a short form version of the Expanded Prostate Cancer Index Composite, and is a validated comprehensive instrument developed to measure the health-related quality of life among men with prostate cancer. EPIC-26 consists of 26 items under 5 domains of urinary incontinence, urinary irritative/obstructive, bowel, sexual, and hormonal.
Answers qualitatively measure patient's bother for each symptom and are then normalized on a scale of 0 (worst) to 100 (best) to calculate domain scores if sufficient input is provided.
Baseline
Group
Value
95% CI
Low Risk
55.27
± 33.41
Intermediate Risk
56.32
± 32.6
1 Month Post Treatment
Group
Value
95% CI
Low Risk
47.46
± 33.58
Intermediate Risk
50.58
± 31.82
6 Months Post Treatment
Group
Value
95% CI
Low Risk
50.06
± 31.91
Intermediate Risk
51.23
± 33.47
12 Months Post Treatment
Group
Value
95% CI
Low Risk
44.86
± 34.82
Intermediate Risk
45.2
± 32.46
24 Months Post Treatment
Group
Value
95% CI
Low Risk
40.77
± 32.15
Intermediate Risk
39.73
± 30.39
36 Months Post Treatment
Group
Value
95% CI
Low Risk
42.5
± 33.57
Intermediate Risk
40.99
± 31.59
48 Months Post Treatment
Group
Value
95% CI
Low Risk
38.3
± 31.56
Intermediate Risk
38.95
± 31.8
60 Months Post Treatment
Group
Value
95% CI
Low Risk
32.22
± 31.16
Intermediate Risk
36.89
± 32.44
Adverse events — posted to ClinicalTrials.gov
Time frame: Adverse event data collected from study enrollment through end of protocol follow-up, including fiducial placement, CyberKnife radiosurgery treatment, and scheduled follow-up visits up to 10 years post-CK treatment..
Reporting threshold: 5%.
Adverse-event reports describe events observed during the trial — not all are caused by the drug.
Low Risk
Serious: 17/112 (15%)
Deaths: 9/112
Intermediate Risk
Serious: 25/147 (17%)
Deaths: 14/147
Serious adverse events (26 terms)
Reaction
System
Low Risk
Intermediate Risk
Other Malignancy
Neoplasms benign, malignant and unspecified (incl cysts and polyps)
The purpose of this study is to investigate the effects of CyberKnife radiosurgery in patients with early stage organ-confined prostate cancer and to evaluate the effects of this treatment on the quality of life over time.
Publications & conference data
3 peer-reviewed publications reference this trial (live from Europe PMC):
Publications: Europe PMC API search by NCT ID, retrieved 10 June 2026
Drug + disease cross-links: matched in real time against Drug Landscape's normalised drug + company + condition tables
Sponsor: as reported to ClinicalTrials.gov by Accuray Incorporated
Last refreshed: 9 May 2023
Drug Landscape aggregates and links these public records for informational use only. Always verify against the primary source before clinical or regulatory decisions. Canonical URL: https://druglandscape.com/trial/NCT00643617.