Focal Radiation Therapy (HDR-Brachytherapy) for the Treatment of Prostate Cancer

Phase II Trial of Focal Radiation Therapy in Patients With Prostate Cancer

This clinical trial tests the effect of focal radiation therapy, high dose rate-brachytherapy (HDR-BT), in treating patients with prostate cancer. Prostate cancer is the most diagnosed cancer in men and there are many treatments available, including surgery and radiation therapy. Although surgery and radiation therapy improve survival urinary and sexual function can be significantly affected and can be long lasting. HDR-BT, a type of focal radiation therapy also known as internal radiation therapy, uses radioactive material placed directly into or near a tumor to kill tumor cells. Giving HDR-BT may be effective in providing local control while reducing side effects in patients with prostate cancer.

Study Overview

• Status: Recruiting
• Conditions: Prostate Adenocarcinoma; Stage II Prostate Cancer AJCC v8; Stage I Prostate Cancer American Joint Committee on Cancer (AJCC) v8
• Intervention / Treatment: Other: Questionnaire Administration; Procedure: Biospecimen Collection; Procedure: Multiparametric Magnetic Resonance Imaging; Procedure: PSMA PET Scan; Radiation: High-Dose Rate Brachytherapy; Procedure: Biopsy Procedure

Detailed Description

PRIMARY OBJECTIVES:

I. Estimate local control. II. Estimate acute/late grade 2+ genitourinary (GU)/gastrointestinal (GI) toxicity.

SECONDARY OBJECTIVES:

I. Prostate specific antigen (PSA) response at 6 weeks after radiation therapy (RT), every 3 months for 24 months, every 6 months to 60 months, then every 8-12 months until 5 years.

II. Clinical progression free survival/biochemical progression free survival at 5 years.

III. Distant metastasis free survival. IV. Development of castration-resistant disease. V. Overall survival. VI. Changes in quality of life VIa. Functional Assessment of Cancer Therapy-Prostate (FACT-P) questionnaire; VIb. Expanded Prostate Cancer Index Composite Short Form (EPIC-26) questionnaire.

OUTLINE:

Patients undergo HDR-BT to dominant prostate lesion on day 1. Treatment repeats at least 3 weeks apart for up to 2 fractions in the absence of disease progression or unacceptable toxicity. Patients also undergo blood sample collection, multiparametric (mp) magnetic resonance imaging (MRI) and optionally prostate-specific membrane antigen (PSMA) positron emission tomography (PET) throughout the study. Additionally, patients may undergo tumor biopsy as clinically indicated throughout the study.

After completion of study treatment, patients are followed up at 6 weeks, every 3 months for the first 2 years, every 6 months for years 3 and 4, then annually thereafter.

• Study Type: Interventional
• Enrollment (Estimated): 45
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • California
    • Los Angeles, California, United States, 90095
      • Recruiting
      • UCLA / Jonsson Comprehensive Cancer Center
      • Contact: Alan C. Lee; Email: alalee@mednet.ucla.edu
      • Principal Investigator: Alan C. Lee

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Histologically confirmed diagnosis of prostate adenocarcinoma within 90 days prior to registration via systematic biopsy
• Multiparametric MRI (mp-MRI) confirmed lesion(s)

• No distant or locally advanced disease on standard staging exams as indicated

  • Bone scan and abdominopelvic computed tomography (CT)/MRI OR
  • PSMA PET
• Eastern Cooperative Oncology Group (ECOG)/Zubrod performance status 0/1 within 60 days prior to enrollment
• Age ≥ 40

Exclusion Criteria:

• Radiographic nodal or distant metastatic disease
• Lesion(s) comprising > 40% of total prostate volume
• Prior radiotherapy to the pelvis
• Gleason score > 6 disease outside intended gross target volume (GTV)/target region(s)

Study Plan

How is the study designed?

Design Details

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

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Treatment (HDR-BT); Patients undergo HDR-BT to dominant prostate lesion on day 1. Treatment repeats at least 3 weeks apart for up to 2 fractions in the absence of disease progression or unacceptable toxicity. Patients also undergo blood sample collection, mpMRI and optionally PSMA PET throughout the study. Additionally, patients may undergo tumor biopsy as clinically indicated throughout the study.

Other: Questionnaire Administration; Ancillary studies; Procedure: Biospecimen Collection; Undergo blood sample collection; Other Names: Biological Sample Collection; Biospecimen Collected; Specimen Collection; Procedure: Multiparametric Magnetic Resonance Imaging; Undergo mpMRI; Other Names: Multiparametric MRI; MP-MRI; mpMRI; Multi-parametric MRI; Procedure: PSMA PET Scan; Undergo PSMA PET; Other Names: PSMA PET; Prostate-specific Membrane Antigen PET; PSMA-Positron emission tomography; Radiation: High-Dose Rate Brachytherapy; Undergo HDR-BT; Other Names: Brachytherapy, High Dose; HDR; High dose brachytherapy (procedure); Procedure: Biopsy Procedure; Undergo tumor biopsy; Other Names: Bx; BIOPSY_TYPE; Biopsy

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of grade 2 or greater genitourinary adverse events (AEs)	Will be defined as the percentage of patients who encounter the AE of specific grade or worse using Common Terminology Criteria for Adverse Events (CTCAE) version (v) 5.0. Will be calculated to indicate the toxicity level of focal radiation therapy (RT), along with the corresponding 95% Clopper-Pearson exact confidence interval.	Up to 6 years
Incidence of grade 2 or greater gastrointestinal AEs	Will be defined as the percentage of patients who encounter the AE of specific grade or worse using CTCAE v 5.0. Will be calculated to indicate the toxicity level of focal RT, along with the corresponding 95% Clopper-Pearson exact confidence interval.	Up to 6 years
Time to first grade 2 or greater adverse event	Will be analyzed as a time-to-event outcome using Kaplan-Meier (KM) methods.	Up to 6 years
Local control rate	Will be defined as lack of biopsy proven progression within target/treated region/lesion. The proportion of patients achieving local control will be estimated along with the corresponding 95% Clopper-Pearson exact confidence interval.	Up to 6 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Prostate specific antigen (PSA) response	PSA changes over time will be assessed via repeated measures analysis of variance (ANOVA). If significant PSA changes over time are identified by repeated measures ANOVA, the individual comparisons between time points will be evaluated via Tukey's Honestly Significant Difference test as the method of accommodating multiple comparisons.	At 3, 6, 12 and 24 months
Biochemical progression free survival	Will be obtained via KM analysis to provide an overview of efficacy for focal RT.	Up to 5 years
Clinical progression free survival	Will be obtained via KM analysis to provide an overview of efficacy for focal RT.	Up to 5 years
Distant metastasis free survival	Will be obtained via KM analysis to provide an overview of efficacy for focal RT.	Up to 5 years
Overall survival	Will be obtained via KM analysis to provide an overview of efficacy for focal RT.	Up to 6 years
Expanded Prostate Cancer Index Composite Short Form questionnaire score	The change of the scores between the time of pre-focal RT and post-focal RT will be assessed via two-sided paired t-test.	Up to 6 years
Patient reported quality of life	Will be evaluated using Functional Assessment of Cancer Therapy-Prostate questionnaire (FACT-P). The FACT-P uses a 5-point Likert scale for scoring, with total scores ranging from 0 to 156. Higher scores indicate better quality of life. The change of the scores between the time of pre-focal RT and post-focal RT will be assessed via two-sided paired t-test.	Up to 6 years

Collaborators and Investigators

• Sponsor: Jonsson Comprehensive Cancer Center
• Investigators: Principal Investigator: Alan C Lee, UCLA / Jonsson Comprehensive Cancer Center

Study record dates

Study Major Dates

• Study Start (Actual): May 11, 2026
• Primary Completion (Estimated): May 11, 2031
• Study Completion (Estimated): May 11, 2032

Study Registration Dates

• First Submitted: March 9, 2026
• First Submitted That Met QC Criteria: March 9, 2026
• First Posted (Actual): March 13, 2026

Study Record Updates

• Last Update Posted (Actual): May 22, 2026
• Last Update Submitted That Met QC Criteria: May 19, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Urogenital Diseases; Genital Diseases; Genital Neoplasms, Male; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Genital Diseases, Male; Prostatic Diseases; Male Urogenital Diseases; Prostatic Neoplasms; Investigative Techniques; Therapeutics; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Surgical Procedures, Operative; Cytological Techniques; Cytodiagnosis; Hydrolases; Enzymes; Enzymes and Coenzymes; Diagnostic Techniques, Surgical; Radiotherapy; Peptide Hydrolases; Metalloproteases; Carboxypeptidases; Exopeptidases; Metalloexopeptidases; Biopsy; Specimen Handling; Brachytherapy; Glutamate Carboxypeptidase II
• Other Study ID Numbers: 25-2298; NCI-2026-01071 (Registry Identifier: CTRP (Clinical Trial Reporting Program))

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No