Two-fraction HDR Monotherapy for Localized Prostate Cancer

September 14, 2026 updated by: University of California, San Francisco

Two-fraction High Dose Rate Brachytherapy as Monotherapy Delivered Three Hours Apart in Localized Prostate Cancer: A Pilot Study

This is a single center single arm prospective pilot study investigating the safety of high dose rate (HDR) brachytherapy as monotherapy delivered in 2 fractions 3 hours apart. HDR monotherapy has been established as safe and effective in this context, however previous studies have delivered 2 fractions on separate days, or at least 6 hours apart. Clinically, this regimen, if shown to be safe and effective in future studies, has the potential to reduce operative resources and logistical stresses on brachytherapy departments.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

PRIMARY OBJECTIVES:

I. To determine the safety of HDR monotherapy 13.5 Gy x 2 fractions delivered 3 hours apart in patients with low and intermediate risk prostate cancer.

SECONDARY OBJECTIVES:

I. To describe the prostate specific antigen (PSA) kinetics associated with HDR brachytherapy monotherapy 13.5 Gy x 2 fractions delivered 3 hours apart for low and intermediate risk prostate cancer.

OUTLINE:

Treatment will be administered on an outpatient basis. All treatment will be delivered over a single day. Participants will be followed for 6 months after last treatment or removal from study, or until death, whichever occurs first. Additional Follow up will be as per usual guidelines for prostate cancer, every 3 months following treatment with PSA for the first year, then every 4 months after year 2, and every 6 months after year 3 until 5 years of follow up are completed.

Study Type

Interventional

Enrollment (Estimated)

17

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • United States
    • California
      • San Francisco, California, United States, 94143
        • Recruiting
        • University of California, San Francisco
        • Principal Investigator:
          • I-Chow Hsu, MD
        • Contact:
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Participants must have histologically or cytologically confirmed diagnosis of prostate adenocarcinoma.
  2. National Comprehensive Cancer Network favorable intermediate risk stratification, defined as one or more intermediate risk factors such as cT2b - cT2c category, grade group 1 or 2, or PSA 10-20 ng/mL, and less than 50% of biopsy cores positive for carcinoma (i.e. for this trial, we will only include systematic biopsy cores, not targeted biopsy cores).
  3. Age >=18 years.
  4. Eastern Cooperative Oncology Group (ECOG) performance status <2 (Karnofsky >60%).
  5. Eligible to undergo High dose rate (HDR) brachytherapy as monotherapy as determined by the treating radiation oncologist.
  6. Ability to understand and the willingness to sign a written informed consent document.
  7. Human immunodeficiency virus (HIV)-infected individuals on effective anti-retroviral therapy with undetectable viral load within 6 months are eligible for this trial.
  8. For participants with evidence of chronic hepatitis B virus (HBV) infection, the HBV viral load must be undetectable on suppressive therapy, if indicated.
  9. Individuals with a history of hepatitis C virus (HCV) infection must have been treated and cured. For individuals with HCV infection who are currently on treatment, they are eligible if they have an undetectable HCV viral load.
  10. Individuals with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial.
  11. Willingness and ability to complete International Prostate Symptom Score questionnaires.

Exclusion Criteria:

  1. Any prior treatment for prostate cancer.
  2. Prior history of pelvic malignancy.
  3. Any prior androgen deprivation therapy.
  4. Is currently receiving any other investigational agents.
  5. Abnormal pre-brachytherapy assessment raising concern for undergoing HDR brachytherapy procedure.
  6. Contraindications to general anesthesia.
  7. Contraindications to radiotherapy.
  8. Prior history of pelvic radiotherapy.
  9. Presence of lymph node or distant metastases.
  10. Prior cryosurgery or cryotherapy to the prostate.
  11. Prior transurethral resection of the prostate (TURP) or transurethral incision within the previous 6 months.
  12. Estimated prostate volume >60 cubic centimeters as determined by transrectal ultrasound or magnetic resonance imaging.
  13. IPSS score of 15 or higher prior to treatment.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: HDR brachytherapy
Participants will receive the same radiotherapy technique, methods, and delivery will as standard of care 3 hours apart instead of receiving the radiotherapy on separate days.
Radiation: High Dose Rate Monotherapy
High dose rate brachytherapy delivered in 13.5 Gy x 2 fractions over a single implant procedure 3 hours apart
Other Names:
  • High dose rate brachytherapy
  • HDR Monotherapy

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Proportion of participants with treatment-related adverse events
Time Frame: Up to 6 months
The proportion of participants with reported grade 3 or higher genitourinary (GU) or gastrointestinal (GI) toxicities, as graded by the NCI Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 will be reported.
Up to 6 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Mean Prostate Specific Antigen (PSA) Nadir
Time Frame: Up to 6 months
The mean (average) PSA nadir after treatment will be reported along with standard deviations.
Up to 6 months
Mean Time to PSA Nadir
Time Frame: Up to 6 months
The mean (average) time to PSA nadir after treatment will be reported along with standard deviations.
Up to 6 months
Mean Change in International Prostate Symptom Score (IPSS) over time
Time Frame: Up to 6 months
The mean change over time on scores for the International Prostate Symptom Score (IPSS) will be reported along with standard deviations. The IPSS measures the severity of lower urinary tract symptoms and erectile function with lower numbers indicating less change in symptoms. Seven questions with scores ranging from 1-5 are summed to create a total score. Scores of 1-7 indicate mild symptoms, scores of 8-19 indicate moderate symptoms, and scores of 20-35 indicate severe symptoms.
Up to 6 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of California, San Francisco

Investigators

  • Principal Investigator: I-Chow Hsu, MD, University of California, San Francisco

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

September 11, 2024

Primary Completion (Estimated)

February 28, 2029

Study Completion (Estimated)

February 28, 2029

Study Registration Dates

First Submitted

December 16, 2022

First Submitted That Met QC Criteria

December 16, 2022

First Posted (Actual)

December 27, 2022

Study Record Updates

Last Update Posted (Actual)

September 17, 2026

Last Update Submitted That Met QC Criteria

September 14, 2026

Last Verified

September 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 23721
  • NCI-2024-01993 (Registry Identifier: NCI Clinical Trials Reporting Program (CTRP))

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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