Safety and Efficacy of 21 Gy, 23 Gy and 25 Gy for High Dose Rate (HDR) Prostate Brachytherapy

Study Overview
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Brief Summary
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The purpose of this research study is to learn more about the outcomes and early and late side effects of treating early stage prostate cancer with high dose rate brachytherapy.

Official Title
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A Phase I/II Dose-escalation Study Evaluating the Safety and Efficacy of 21 Gy, 23 Gy and 25 Gy for High Dose Rate (HDR) Prostate Brachytherapy

Conditions
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Prostate Cancer, Prostate Neoplasm

Intervention / Treatment
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* Radiation: HDR brachytherapy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Histologically or cytologically confirmed diagnosis of early stage prostate cancer. Must be considered either low-risk (T1-T2a, Gleason ≤ 6, PSA < 10 ng/mL) or favorable intermediate-risk (Gleason 3 +4 = 7, percentage of positive biopsy cores < 50%, no more than one NCCN intermediate risk factor). Prior androgen deprivation therapy is allowed and may have been initiated up to 6 months prior to the date of the HDR implant. The complete duration of androgen deprivation therapy can range from 4 months to 36 months provided it has been initiated no more than 6 months prior to the date of the HDR implant. At least 18 years of age. ECOG performance status ≤ 2 Able to understand and willing to sign an IRB approved written informed consent document (or that of legally authorized representative, if applicable). Exclusion Criteria: Prior radiation therapy to the prostate or lower pelvis encompassing the prostate. A history of other malignancy ≤ 5 years previous with the exception of basal cell or squamous cell carcinoma of the skin which were treated with local resection only. Currently receiving any other investigational agents. Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, or cardiac arrhythmia. Unable to undergo general, spinal or local anesthesia. Prior TURP with a sufficiently large defect that would compromise the integrity of the implant per clinician's assessment.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Non-Randomized
Intervention Model: Sequential Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: HDR brachytherapy - 21 Gy<br>-All patients will be treated with a single implant and single HDR fraction. Treatment will be delivered within a single 24-hour period measured from the beginning of the implant procedure. All patients will receive a dose of 21 Gy. | Radiation: HDR brachytherapy<br>* Dose constraints for 21 Gy: Bladder and rectum: V70 < 1 cc Urethra: V115 < 1 cc V135: 0% Dose constraints for 23 Gy: Bladder and rectum: V65 < 1 cc Urethra: V105 < 1 cc V125: 0% Dose constraints for 25 Gy: Prostate V100 >90% (>95% preferred) Bladder and rectum: V70 < 1 cc, Dmax <115% Urethra: V110 < 1 cc, Dmax <120%<br>|
| Experimental: HDR brachytherapy - 23 Gy<br>-All patients will be treated with a single implant and single HDR fraction. Treatment will be delivered within a single 24-hour period measured from the beginning of the implant procedure. All patients will receive a dose of 23 Gy. | Radiation: HDR brachytherapy<br>* Dose constraints for 21 Gy: Bladder and rectum: V70 < 1 cc Urethra: V115 < 1 cc V135: 0% Dose constraints for 23 Gy: Bladder and rectum: V65 < 1 cc Urethra: V105 < 1 cc V125: 0% Dose constraints for 25 Gy: Prostate V100 >90% (>95% preferred) Bladder and rectum: V70 < 1 cc, Dmax <115% Urethra: V110 < 1 cc, Dmax <120%<br>|
| Experimental: HDR brachytherapy - 25 Gy<br>-All patients will be treated with a single implant and single HDR fraction. Treatment will be delivered within a single 24-hour period measured from the beginning of the implant procedure. All patients will receive a dose of 25 Gy. | Radiation: HDR brachytherapy<br>* Dose constraints for 21 Gy: Bladder and rectum: V70 < 1 cc Urethra: V115 < 1 cc V135: 0% Dose constraints for 23 Gy: Bladder and rectum: V65 < 1 cc Urethra: V105 < 1 cc V125: 0% Dose constraints for 25 Gy: Prostate V100 >90% (>95% preferred) Bladder and rectum: V70 < 1 cc, Dmax <115% Urethra: V110 < 1 cc, Dmax <120%<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Biochemical control experienced by patients with prostate cancer treated with an HDR implant | -Response will be determined by PSA. The Phoenix definition will be used for determining biochemical failure: a rise of 2 ng/mL or more above the PSA nadir | Through 3 years after implant | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rate of acute toxicity experienced by patients with prostate cancer treated with an HDR implant | -The descriptions and grading scales found in the revised NCI Common Terminology Criteria for Adverse Events (CTCAE) version 4.0 will be utilized for all toxicity reporting. | Through 3 years after implant | 
| Rate of late toxicity experienced by patients with prostate cancer treated with an HDR implant | -The descriptions and grading scales found in the revised NCI Common Terminology Criteria for Adverse Events (CTCAE) version 4.0 will be utilized for all toxicity reporting. | Through 3 years after implant |