NCT06822491

Early Magnetic Resonance Imaging Response of the Dominant Intraprostatic Lesion After Online Adaptive Stereotactic Body Radiotherapy for Localized Prostate Cancer and Correlation With Prostate Specific Antigen Response

Early Magnetic Resonance Imaging Response of the Dominant Intraprostatic Lesion After Online Adaptive Stereotactic Body Radiotherapy for Localized Prostate Cancer and Correlation With Prostate Specific Antigen Response (PRODART)

• Status: Active Not Recruiting
• Phase: —
• Study type: Observational
• Enrollment: 28 (estimated)
• Sponsor: University of Zurich · Academic / Other
• Sex: Male
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

The aim of this phase II study is to determine the early multiparametric magnetic resonance imaging response of the dominant intraprostatic lesion and correlate these findings with prostate specific antigen response in patients with intermediate to (very) high risk localized prostate cancer treated with online adaptive stereotactic radiotherapy without intraprostatic fiducial markers.

Detailed description

Background: Stereotactic body radiotherapy (SBRT) is an established standard of care treatment for localized prostate cancer. Recent pathological studies suggest the presence of a dominant intraprostatic lesion (DIL) within the prostate, which serve as a central driver of tumor aggressiveness and recurrence after treatment. Prostate-specific antigen (PSA) monitoring is the cornerstone of follow-up, though time to PSA nadir after SBRT can extend to 3 years. Methods: This phase II observational study aims to evaluate the correlation between PSA response and early multiparametric magnetic resonance imaging (mpMRI) changes of the DIL(s) at 6- or 9-months following online adaptive SBRT for intermediate to (very) high risk localized prostate cancer. The primary outcome is the achievement of local control as assessed by mpMRI at 6 months post-SBRT or, if necessary, at 9 months post-SBRT (in case of image non complete response at 6 months). A complete imaging response is defined as the disappearance of all morphological and functional mpMRI changes of PIRADS (Prostate Imaging Reporting and Data System) ≥3 lesion(s) correlating with Gleason ≥7a pathology. No confirmatory biopsies will be conducted. The required sample size for this study will be 28 patients, assuming a complete response rate of 80% at 6 months, targeting an acceptable margin of error with 95% confidence, and a margin of error of 15%.

Conditions

• Prostate Carcinoma
• Localized Prostate Adenocarcinoma
• Stereotactic Body Radiotherapy
• Stereotactic Radiotherapy
• Magnetic Resonance Imaging
• Multiparametric MRI

Timeline

• Start date: 2024-08-20
• Primary completion: 2026-06-01
• Completion: 2031-06-01
• First posted: 2025-02-12
• Last updated: 2025-12-23

Locations

1 site across 1 country: Switzerland