Hypofractionated Radiotherapy With a Focal Microboost for High-Risk and Locally Advanced Prostate Cancer

This study is for adult men with previously untreated high risk, very high risk, or pelvic lymph node positive prostate cancer. The purpose of this study is to evaluate the safety and effectiveness of the combination of two emerging radiation treatment techniques (hypofractionated radiotherapy and microboost technique). Participation will include standard of care visits along with questionnaires and blood draws completed for research purposes. There is optional banking of blood and prostate biopsy tissue which will not require extra biopsies. Participation in this study is anticipated to last approximately 6 weeks with follow up every three months for two years then twice yearly for years 3-5.

Study Overview

• Status: Recruiting
• Conditions: Prostate Cancer; Prostate Cancer Patients Treated by Radiotherapy
• Intervention / Treatment: Radiation: Hypofractionated radiation with a microboost

• Study Type: Interventional
• Enrollment (Estimated): 46
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Harriet Eldredge-Hindy Eldredge-Hindy, MD; Phone Number: 8437926382; Email: eldredge@musc.edu

Study Locations

• United States
  • South Carolina
    • Charleston, South Carolina, United States, 29425
      • Recruiting
      • Medical University of South Carolina Hollings Cancer Center
      • Contact: Casey Charlton; Email: charltoc@musc.edu

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

1. Provision of signed and dated informed consent form.
2. Stated willingness to comply with all study procedures and availability for the duration of the study.
3. Biologically male patients aged 18 years and older.
4. Ability to receive pelvic radiotherapy and be willing to adhere to the protocol regimen.
5. Previously untreated prostate cancer (with cytotoxic chemotherapy, cryotherapy, ablative treatment, surgical or radiation therapy). Prior transurethral resection of prostate (TURP) is permitted if 90 days or more prior to the start of radiotherapy.

6. Localized or locally advanced prostate cancer meeting NCCN criteria for high risk, very high risk or non-metastatic, pelvic lymph node positive defined as having at least one or more of the following:

   1. PSA >20 ng/mL prior to starting ADT.
   2. cT3a-T4 by digital exam or imaging.
   3. Gleason score of 8-10 (grade group 4 or 5).
   4. Staged as N1M0 by the treating investigator (pelvic lymph node positive, below the aortic bifurcation) based on soft tissue imaging within 120 days prior to registration (may include CT, MRI or PSMA PET/CT, of fluciclovine choline PET/CT).
7. History and physical exam within 120 days prior to registration.
8. ECOG performance status 0-2.
9. Be able to undergo MRI of the prostate and/or pelvis as a component of RT planning.
10. Have at least one MRI visible target for microboost (PI-RADS≥ 4 version 2.0).
11. Bone and soft tissue imaging as clinically indicated for staging within 120 days prior to registration.
12. For males: use of condoms or other methods to ensure effective contraception with partner during radiation and for six months after completion of radiation.

13. Adequate hematologic function within 120 days prior to registration as defined by:

    1. hemoglobin >=9.0 g/dL independent of transfusion, and
    2. platelet count >= 100,000 x 10 ^9/microliter independent of transfusion.
14. Adequate hepatic function within 120 days prior to registration defined as total bilirubin <2 x institutional upper limits of normal (ULN is 1.2 mg/dL). If labs are done at outside institution, total bilirubin should be <2.4.
15. Agreeable and eligible to receive long term (defined as 12-36 months) ADT as a standard component of prostate cancer therapy.

Exclusion Criteria:

• 1. Concurrent use of testosterone supplementation unless discontinued by time of registration.

  2. Definitive radiologic evidence of metastatic disease outside of the pelvic nodes on conventional imaging (bone scan, CT scan, MRI).

  3. Prior pelvic radiotherapy. 4. Pre-existing conditions or overall health status which disqualifies the patient from curative intent-RT. Patients with life expectancy less than 5 years are not eligible.

  5. Treatment with another investigational prostate cancer therapy within 12 months.

  6. Prior total prostatectomy, cryotherapy, high-intensity focused ultrasound, irreversible electroporation, MRI ablation, laser ablation, transurethral ultrasound ablation, aquablation directed towards the prostate for any prostate disease or condition.

  7. Prior or concurrent invasive pelvic malignancy (except non-melanomatous skin cancer) or lymphomatous or hematogenous malignancy, unless disease free for a minimum of 5 years.

  8. Any condition that, in the opinion of the investigator, would preclude participation in this study.

  9. Prior pharmacologic androgen ablation for prostate cancer is allowed only if the onset of androgen ablation (both LHRH agonist and oral anti-androgen) is ≤ 90 days prior to registration.

  10. Inability to undergo implantation of gold fiducial markers or rectal spacer gel.

  11. Patients with a prior or concurrent malignancy whose natural history or treatment has the potential to interfere with the safety or efficacy assessment of the investigational regimen.

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: Hypofractationed pelvic radiation with microboost

Radiation: Hypofractionated radiation with a microboost; Patients will receive 25 fractions of external beam radiation therapy. Dose to the elective lymph nodes will be 45 Gy in 25 fractions. Dose to the prostate and portions of the seminal vesicles will be 68 Gy in 25 fractions. A microboost to up to three dominant intraprostatic nodules will be given in 25 fractions (dose range 70-83 Gy). Simultaneous integrated boost to sites of pelvic lymphadenopathy may be given. Androgen deprivation therapy will be per local standard of care.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
CTCAE grade 2 or higher acute genitourinary toxicity	1 month post radiation

Secondary Outcome Measures

Outcome Measure	Time Frame
grade 2 or higher acute GI toxicity, late GU toxicity and late GI toxicity	5 years
PSA failure rate	2 years
death from any cause	5 years
Mean change in Sexual Health Inventory for Men (SHIM) score	5 years
Mean change in EPIC-26 sexual domain score from baseline	1 year

Collaborators and Investigators

• Sponsor: Medical University of South Carolina

Study record dates

Study Major Dates

• Study Start (Actual): February 2, 2026
• Primary Completion (Estimated): January 1, 2029
• Study Completion (Estimated): January 1, 2034

Study Registration Dates

• First Submitted: November 24, 2025
• First Submitted That Met QC Criteria: December 29, 2025
• First Posted (Actual): January 8, 2026

Study Record Updates

• Last Update Posted (Actual): February 5, 2026
• Last Update Submitted That Met QC Criteria: February 3, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Prostate cancer; hypofractionated; Microboost
• 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
• Other Study ID Numbers: 104214; Pro00147655 (Other Identifier: MUSC IRB)

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
• product manufactured in and exported from the U.S.: Yes