Comparing PSMA PET/CT and MRI-RSI for Finding and Outlining Tumors Inside the Prostate in Men With Newly Diagnosed Prostate Cancer (PRIDE2-PC)

Prospective Comparison of PSMA PET/CT and MRI-RSI (Restriction Spectrum Imaging) for Intraprostatic Tumor Detection and Delineation in Primary Prostate Cancer Patients

The detection and delineation of the intraprostatic tumor burden plays a crucial role in the personalized treatment of primary prostate cancer. The current gold standard multiparametric magnetic resonance imaging (mpMRI) is used to guide targeted prostate biopsies for initial diagnostic work up and for definitive focal dose-escalated radiotherapy in intermediate and high-risk prostate cancer patients.

However, mpMRI might underestimate the tumor volume and manual gross tumor volume delineation based on mpMRI underlies significant interobserver variability. Thus, novel imaging modalities are warranted to increase the detection rate and/or decrease the interobserver variability during tumor delineation.

This study will prospectively compare two promising advanced medical imaging methods: MRI-RSI and PSMA PET with the current gold-standard mpMRI for tumor detection and delineation in primary prostate cancer patients.

Study Overview

• Status: Recruiting
• Conditions: Prostate Cancer
• Intervention / Treatment: Diagnostic test: MRI; Diagnostic test: 18F-PSMA1007 PET-CT; Diagnostic test: MR-guided TRUS Prostate biopsy

• Study Type: Interventional
• Enrollment (Estimated): 50
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: CONSTANTINOS ZAMBOGLOU, DR; Phone Number: +35725208000; Email: kristis.vevis@goc.com.cy

Study Locations

• Cyprus
  • Limassol, Cyprus, 4108
    • Recruiting
    • German Oncology Center
    • Contact: CONSTANTINA CLOCONI; Phone Number: +35725208000; Email: constantina.cloconi@goc.com.cy

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Newly diagnosed and histologically confirmed primary prostate cancer
• NCCNv4.2024 risk groups: unfavorable intermediate risk, high-risk and very high-risk
• Males, age ≥ 18 years
• ECOG performance status 0-2
• Estimated life expectancy ≥ 5 years
• PSMA-PET/CT-hybrid imaging performed <3 months
• MRI-targeted biopsy on PIRADs v2.1 lesion ≥3 performed <6 months

Exclusion Criteria:

• Contraindications for MRI imaging
• No visible tumor on PSMA PET and mpMRI (defined by PIRADs v2.1 ≤2 lesion)
• TUR-P of the prostate <1 year ago
• Initial PSA >100 ng/ml
• History of cancer (exception: localized skin tumours, tumours treated ≥5 years previously with curative intent and no evidence of recurrent disease)
• Previous radiation therapy to the pelvis
• ADT or ADT + other systemic therapy before inclusion

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• 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: Prospective comparison of PSMA PET/CT and MRI-RSI for patients with primary prostate cancer; MRI-RSI imaging of the prostate (non-invasive)	Diagnostic test: MRI; MRI-RSI imaging of the prostate (non-invasive); Diagnostic test: 18F-PSMA1007 PET-CT; PET scan according to standard protocol; Diagnostic test: MR-guided TRUS Prostate biopsy; Biopsy according to standard protocol

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sensitivity	Sensitivity for PSMA PET, conventional mpMRI, MRI-RSI and combined modalities will be calculated on a prostate segment (n=6) level. The prostate cancer distribution in targeted biopsy cores will serve as the ground truth, calculated with the ratio of true positives to the total number of segments with the disease (true positives + false negatives).	24 months
Absolute GTV volumes	Conventional mpMRI, MRI-RSI and PSMA-PET derived absolute GTV volumes in ml	24 months
Specificity	Specificity for PSMA PET, conventional mpMRI, MRI-RSI and combined modalities will be calculated on a prostate segment (n=6) level. The prostate cancer distribution in targeted biopsy cores will serve as the ground truth, calculated with the ratio of true negatives to the total number of segments without the disease (true negatives + false positives).	24 months
ROC-AUC	ROC-AUC for PSMA PET, conventional mpMRI, MRI-RSI and combined modalities on a segment level in comparison with prostate cancer distribution in targeted biopsy cores on a 6 segment level (ground truth). It will be calculated by integrating the area under the TPR (Sensitivity) vs FPR (1-Specificity) curve	24 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Dice Sorensen Coefficient (DSC)	The DSC is defined as followed: twice the size of the intersection of two sets, divided by the sum of the sizes of the two sets. The DSC will be used to compare different GTVs and likewise analyse the geometric overlap and the interobserver variance.	24 months
Dose volume histogram parameters in volume (ml) in relation to Gray	Comparison of planning parameters and DVH metrics after PSMA PET and/or MRI-RSI based radiotherapy for target volumes and organs at risk.	24 months
Correlation coefficient (Spearman or Pearson)	Quantitative imaging parameters from PSMA-PET, MRI-RSI and mpMRI images will be extracted and cross correlated with the ArteraAI MMAI test score (if available), Prolaris, the Ki-67 staining, the ISUP grade, serum PSA levels and the cTstage	24 months

Collaborators and Investigators

• Sponsor: German Oncology Center, Cyprus

Study record dates

Study Major Dates

• Study Start (Actual): August 18, 2025
• Primary Completion (Estimated): January 31, 2027
• Study Completion (Estimated): July 31, 2027

Study Registration Dates

• First Submitted: August 13, 2025
• First Submitted That Met QC Criteria: April 28, 2026
• First Posted (Actual): May 6, 2026

Study Record Updates

• Last Update Posted (Actual): May 6, 2026
• Last Update Submitted That Met QC Criteria: April 28, 2026
• Last Verified: April 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
• Other Study ID Numbers: ΕΕΒΚ/ΕΠ/2025/20

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: No