Clinical trial · Interventional
Single-Dose Image-Guided Radiotherapy With Urethral Sparing and DIL Boost for Intermediate-Risk Prostate Cancer (PROSINT II)
Phase II Study of Single-Dose Image-Guided Radiotherapy (SDRT) With Urethral Sparing and Dose-Escalated Dominant Intraprostatic Lesion Simultaneous Integrated Boost for Intermediate-Risk Prostate Cancer (PROSINT II)
- Source
- ClinicalTrials.gov
- Retrieved
- Sep 8, 2026
- Layer
- normalized (units and labels harmonized; values unchanged)
- Run
- ING-CLINICALTRIALS-20260908-000001
Summary
Brief summary (as posted)
This prospective single-arm phase II study evaluates the safety, feasibility, quality-of-life effects, PSA kinetics, imaging response, and clinical outcomes of definitive ultra-high dose single-fraction external beam radiation therapy in patients with biopsy-proven NCCN intermediate-risk localized adenocarcinoma of the prostate. All eligible patients receive image-guided volumetric modulated arc radiotherapy with urethral sparing and organ-motion mitigation. Treatment consists of 24 Gy in one fraction to the whole prostate gland and proximal seminal vesicles. Patients with NCCN unfavorable intermediate-risk disease and an imaging-defined dominant intraprostatic lesion may receive a PSMA PET/CT-guided simultaneous integrated boost to the dominant intraprostatic lesion in sequential dose-escalation cohorts, up to 30 Gy, while maintaining protocol-defined organ-at-risk constraints. A rectal balloon with air filling is used for prostate target immobilization and anatomical reproducibility, and a urethral catheter loaded with beacon transponders is used to identify the urethra, support urethral sparing, and enable online target tracking. Toxicity is assessed using CTCAE v4.0, and patient-reported outcomes are assessed using EPIC-26, IPSS, and IIEF questionnaires. PSA is measured at protocol-defined follow-up visits. Multiparametric MRI is performed at baseline and at 12 and 24 months after treatment. Participants are followed for a minimum of 5 years.
Conditions
Conditions (1)
Free-text conditions as registered, with the CancerIndex entity they were reconciled to and the match type.
| Condition (as posted) | Mapped entity | Match | Confidence |
|---|---|---|---|
| Prostate Cancer | Malignant Prostate Neoplasm | CURATED_EXACT | 0.92 |
Interventions
Interventions (5)
| Intervention | Type | Mapped drug | Match |
|---|---|---|---|
| IGRT-VMAT / SDRT 24 Gy in 1 fraction | Radiation | — | UNRESOLVED |
| Planning MRI for organ at risk and target definition | Diagnostic Test | — | UNRESOLVED |
| PSMA PET/CT for DIL definition and/or staging where protocol-required | Diagnostic Test | — | UNRESOLVED |
| Rectal balloon with air filling | Device | — | UNRESOLVED |
| Urethral catheter loaded with beacon transponders | Device | — | UNRESOLVED |
Design
Arms and outcomes
Arms (1)
- type
- EXPERIMENTAL
- label
- Single-dose IGRT-VMAT with urethral sparing ± PSMA-guided DIL-SIB
- description
- Participants receive single-fraction image-guided volumetric modulated arc radiotherapy to the whole prostate gland and proximal seminal vesicles, with urethral sparing, rectal-balloon immobilization, and online tracking using a urethral catheter loaded with beacon transponders. The whole-gland prescription dose is 24 Gy in 1 fraction. Participants with NCCN unfavorable intermediate-risk disease and an imaging-defined dominant intraprostatic lesion may receive PSMA PET/CT-guided simultaneous integrated boost to the dominant intraprostatic lesion in sequential cohorts to 26.4 Gy, 28.8 Gy, or 30 Gy, while satisfying the same organ-at-risk constraints.
- interventionNames
- Radiation: IGRT-VMAT / SDRT 24 Gy in 1 fraction
- Device: Rectal balloon with air filling
- Device: Urethral catheter loaded with beacon transponders
- Diagnostic Test: PSMA PET/CT for DIL definition and/or staging where protocol-required
- Diagnostic Test: Planning MRI for organ at risk and target definition
Primary outcomes (1)
- measure
- Incidence of acute grade ≥2 GU and/or GI toxicity
- timeFrame
Eligibility
Eligibility (as posted)
- Sex
- Male
- Minimum age
- 18 Years
Show eligibility criteria text
Inclusion criteria Participants must meet all of the following criteria: Signed study-specific informed consent form Histologic confirmation of adenocarcinoma of the prostate by biopsy Biopsy ISUP grade 1-3 Biopsy-proven localized intermediate-risk prostate cancer according to NCCN criteria No previous hormonal therapy PSA ≤20 ng/mL Staging multiparametric MRI confirmation of AJCC cT1c-cT2c disease, with no radiographic evidence of cT3, cT4, or N1 disease No direct evidence of regional or distant metastases after appropriate staging studies Age ≥18 years Performance status 0-2 IPSS score ≤15; alpha-blockers allowed CT- or ultrasound-based prostate gland volume estimate ≤100 grams Exclusion criteria Participants with any of the following are ineligible: Positive lymph nodes or metastatic disease from prostate cancer on imaging studies MRI evidence of radiographic T3, T4, or N1 disease Biopsy ISUP grade ≥4 Previous pelvic radiotherapy Previous surgery for prostate cancer Previous transurethral resection of the prostate within 3 months Contraindication to protocol-required Foley catheter placement, rectal-balloon placement, MRI, PSMA PET/CT where required, or treatment immobilization/tracking procedures Active urinary tract infection, unresolved acute prostatitis, or other acute condition judged by the investigator to make simulation or SDRT unsafe until resolved Previous hormonal therapy History of Crohn's disease or ulcerative colitis Previous significant obstructive symptoms Significant psychiatric illness CT- or ultrasound-estimated prostate volume \>100 grams Severe active comorbidity judged by the investigator to preclude protocol treatment
References
Publications (0)
Data not yet available