MRI-based Focal Intraprostatic Simultaneous Integrated Boost (SIB) Intensification With De-escalated Adaptive-risk SBRT for Patients With Low to Intermediate Risk Prostate Cancer

NCT07644598 | Not Yet Recruiting Phase 2 DMC FDA Device

• 1 other identifier: STUDY00009733
• Study Type: interventional
• Target: 58
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this clinical trial is to determine the safety of stereotactic body radiation therapy (SBRT) microboost technique in patients with low to intermediate risk prostate cancer. The main question it aims to answer is: Is microboost SBRT with whole gland de-escalation both safe and effective in managing patients with low to intermediate-risk prostate cancer while maintaining acceptable toxicity levels? All patients will receive microboost SBRT at a dose of 45 Gy delivered in 5 fractions in up to 4 MRI-defined lesions. Patients (Arm 1) with highest grade disease in the microboost target lesion in the absence of GG2-3 beyond the microboost target (only GG1 disease can be present outside of the microboost region) will receive whole gland de-escalation at a dose of 30 Gy delivered in 5 fractions. Patients (Arm 2) with highest grade disease outside of the target lesion will receive whole gland de-escalation at a dose of 35 Gy delivered in 5 fractions. Participants will be treated every other day over a two week period and then follow up after radiation treament for up to 5 years. Participants will be asked to complete questionnaires and provide blood and urine samples for research purposes.

Conditions

Prostate Cancer; Localized Prostate Carcinoma

Keywords

Localized prostate cancer

Outcome Measures

Primary Outcomes (1)

• Incidence of acute grade 2 or higher genitourinary toxicity

  Safety of the microboost technique will be determined based on the incidence of acute grade 2 or higher genitourinary adverse events (AEs). AEs will be assessed and graded according to the current version of the Common Terminology Criteria for Adverse Events (CTCAE) or severity grade when CTCAE grading does not exist. Grade 1 to 5 will be used to characterize the severity of the AE. If CTCAE grading does not exist for an AE, the severity of mild, moderate, severe, life-threatening and death due to the AE, corresponding respectively to Grades 1 - 5, will be used.

  during treatment through 90 days after radiation treatment

Secondary Outcomes (11)

• Incidence of acute grade 2 or higher gastrointestinal (GI) toxicity

  Up to 5 years

• Incidence of late grade 2 or higher genitourinary (GU) or gastrointestinal (GI) toxicity

  Up to 5 years

• Incidence of late grade 3 or higher genitourinary or gastrointestinal toxicity

  Up to 5 years

• PSA (Prostate-specific antigen) nadir

  at 2 years and 5 years

• Biochemical failure (BF)

  at 2 years and 5 years

Study Arms (2)

Arm 1- Low Risk

EXPERIMENTAL

Patients enrolled to arm 1 will have low risk prostate cancer without Grade Group 2-3 (GG2-3) outside of the microboost target(s). Patients in arm 1 will receive microboost SBRT at a dose of 45 Gy delivered in 5 fractions in up to 4 MRI-defined lesions plus whole gland de-escalation at a dose of 30 Gy delivered in 5 fractions.

Radiation: Microboost SBRT; Radiation: Whole gland de-escalation 30 Gy

Arm 2- Intermidiate Risk

EXPERIMENTAL

Patients enrolled to arm 2 will have intermidiate risk prostate cancer with grade group 2-3 disease outside of the microboost target(s). Patients in arm 2 will receive microboost SBRT at a dose of 45 Gy delivered in 5 fractions in up to 4 MRI-defined lesions plus whole gland de-escalation at a dose of 35 Gy delivered in 5 fractions.

Radiation: Microboost SBRT; Radiation: Whole gland de-escalation 35 Gy

Interventions

Whole gland de-escalation 30 Gy RADIATION

Whole gland de-escalation at a dose of 30 Gy delivered in 5 fractions.

Arm 1- Low Risk

Whole gland de-escalation 35 Gy RADIATION

Whole gland de-escalation at a dose of 35 Gy delivered in 5 fractions

Arm 2- Intermidiate Risk

Microboost SBRT RADIATION

Microboost SBRT at a dose of 45 Gy for 5 fractions

Arm 1- Low Risk; Arm 2- Intermidiate Risk

Eligibility Criteria

• Age: 18 Years+
• Sex: male
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Patients age 18 or older.
• Patients with an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2
• Patients with histologically confirmed adenocarcinoma of the prostate who have not received prior pelvic radiation therapy or prostatectomy.
• Patients with low to intermediate risk group defined by the NCCN (National Comprehensive Cancer Network) guidelines as follows:
• Low risk prostate cancer:
• cT1-cT2a (AJCC; 8TH edition, 2017)
• Grade Group 1 (GG1)
• PSA \<10 ng/mL
• Intermediate risk prostate cancer:
• cT2b-cT2c (AJCC; 8TH edition, 2017)
• Grade Group 2 (GG2) or Grade Group 3 (GG3)
• PSA 10-20 ng/mL
• Patients with unfavorable intermediate risk prostate cancer defined by the NCCN guidelines are recommended to undergo a PSMA (Prostate-Specific Membrane Antigen) PET, then the PSMA PET must show localized disease.
• Patients must have preferably undergone a standard of care pretreatment MRI fusion biopsy\* to identify visible intraprostatic lesions and confirm the absence of regional or distant metastatic disease, with criteria as follows:
• Ability to undergo an MRI fusion biopsy;

You may not qualify if:

• Patients with evidence of disease Grade Group 4 (GG4) or higher.
• Patients with PSA \>20 ng/mL.
• Patients with evidence of clinical stage T3a+ or gross extracapsular extension on the diagnostic MRI.
• Patients who received prior or concurrent androgen deprivation therapy for prostate cancer.
• Patients with more than 4 disease foci identifiable on MRI.
• Patients with evidence of metastatic disease on imaging (e.g., bone scan, PSMA PET scan, or MRI/CT scan).
• Patients with ineligibility to undergo an MRI due to:
• The presence of a cardiac pacemaker, defibrillator, or other implanted metallic or electronic device which is considered MRI unsafe;
• Severe claustrophobia;
• Inability to lie flat for the duration of the study;
• Metallic implant or device in the pelvis that might distort the local magnetic field and compromise quality of MRI;
• Any other reason as determined by the investigator or treating physician.
• Patients with an I-PSS score \>20 as defined by any pre-treatment IPSS questionnaire.
• Patients with a prior history of transurethral resection of the prostate, TURP, Urolift, or other similar trans-urethral LUTS management procedure within the last 6 months.
• Patients with a prior history of severe urethral stricture.

Sponsors & Collaborators

• Georgetown University: lead

Study Sites (1)

Lombardi Comprehensive Cancer Center, Georgetown University

Washington D.C., District of Columbia, 20007, United States

Location

MeSH Terms

Conditions

Prostatic Neoplasms

Condition Hierarchy (Ancestors)

Genital Neoplasms, Male; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Genital Diseases, Male; Genital Diseases; Urogenital Diseases; Prostatic Diseases; Male Urogenital Diseases

Central Study Contacts

Jonathan Lischalk, MD

CONTACT

2026879194; jonathan.w.lischalk@gunet.georgetown.edu

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: May 28, 2026
• First Posted: June 12, 2026
• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): January 1, 2028
• Study Completion (Estimated): January 1, 2035
• Last Updated: June 12, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)