Adaptive Stereotactic Radiotherapy for Localized Prostate Cancer (SPAR)

January 8, 2026 updated by: Clinique Sainte Clotilde

Intérêt de la radiothérapie Adaptative en stéréotaxie Prostatique

This study evaluates whether adaptive stereotactic body radiotherapy (SBRT) provides dosimetric advantages compared to non-adaptive SBRT in localized prostate cancer. Five low-dose CT scans are performed before each SBRT session to assess anatomical variations (bladder filling, rectal volume) and determine if a dosimetric recalculation would have been required. The study also evaluates cumulative dose to organs at risk, patient-reported quality of life over 24 months, and overall and recurrence-free survival.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

100

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Reunion
      • Saint-Denis, Reunion, 97404
        • Recruiting
        • Clinique sainte Clotilde
        • Contact:
        • Principal Investigator:
          • Mickael Begue, Doctor
        • Sub-Investigator:
          • Fabien Dutheil, Doctor
        • Sub-Investigator:
          • Olivier Maillot, Doctor
        • Sub-Investigator:
          • Gilles Baumont, Doctor

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Male aged ≥60 years
  • Localized prostate cancer of low or intermediate risk (T1-T2)
  • Gleason score 6-7
  • PSA <15 ng/mL
  • No evidence of metastatic disease
  • Radiotherapy indicated for prostate cancer
  • Affiliated with or benefiting from a French social security system
  • French-speaking patient
  • Patient appropriately informed and having signed a written informed consent form

Exclusion Criteria:

  • Unable to read, write, or understand French
  • Vulnerable patient as defined by Article L1121-6 of the French Public Health Code
  • Adult under guardianship, curatorship, or legal protection ("sauvegarde de justice")
  • Patient unable to personally provide informed consent according to Article L1121-8 of the French Public Health Code
  • Patient already included in another interventional study that could interfere with study outcomes
  • History of urological (prostate) or digestive surgery that could influence study outcomes
  • Refusal to sign the written informed consent form

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: Patients treated by SBRT with pre-session low-dose CT
Five low-dose, non-contrast CT scans performed immediately before each SBRT session (≈10 min before treatment) to assess anatomical variations impacting target volume and organ-at-risk dosimetry.
Other: Low-dose CT imaging before each SBRT session
Five low-dose, non-contrast CT scans performed immediately before each SBRT session (≈10 min before treatment) to assess anatomical variations impacting target volume and organ-at-risk dosimetry.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Proportion of patients requiring dosimetric recalculation due to anatomical variations
Time Frame: At each of the 5 SBRT sessions (10 days max) Based on scanners low-dose comparison.

Percentage of patients for whom at least one stereotactic body radiotherapy (SBRT) fraction would have required a dosimetric recalculation due to anatomical variations (bladder filling and/or rectal emptying), based on comparison between the initial treatment plan and pre-treatment low-dose CT scans acquired before each SBRT fraction (5).

This outcome reflects the potential benefit of an adaptive radiotherapy approach compared to a non-adaptive strategy.
At each of the 5 SBRT sessions (10 days max) Based on scanners low-dose comparison.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Cumulative delivered dose to Organs at Risk (OARs)
Time Frame: From baseline CT + all 5 fraction low-dose CT scans. (up to 10 days)

Definition:

Quantitative assessment of the dose actually delivered to each OAR across all fractions, based on dose-volume parameters derived from the low-dose CTs and DVH (Dose-Volume Histogram) analyses.

OARs and parameters include:

Rectum Maximum dose (0.03 cc) Dose to 3 cc Dose to 10%, 20%, and 50% of the volume

Bladder Maximum dose (0.03 cc) Dose to 10% and 50% of the volume Penile bulb Maximum dose Dose to 3 cc

Femoral heads Dose to 10 cc (combined left and right) Maximum dose

Bowel (GETUG-14 constraints) D5cc D1cc

Urethra Maximum dose
From baseline CT + all 5 fraction low-dose CT scans. (up to 10 days)
Change from baseline in global quality of life (EORTC QLQ-C30)
Time Frame: Time Frame: Baseline (pre-radiotherapy) 1 month 3 months 6 months 12 months 18 months 24 months post-radiotherapy

Change from baseline in global quality of life assessed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30).

Score range: 0-100 Higher scores indicate better quality of life.
Time Frame: Baseline (pre-radiotherapy) 1 month 3 months 6 months 12 months 18 months 24 months post-radiotherapy
Survival outcomes
Time Frame: 1, 3, 6, 12, 18, 24 months post-radiotherapy
Overall Survival (OS): Death from any cause.
1, 3, 6, 12, 18, 24 months post-radiotherapy
Recurrence-Free Survival (RFS)
Time Frame: 1, 3, 6, 12, 18, 24 months post-radiotherapy
Clinical, biochemical, or radiological recurrence.
1, 3, 6, 12, 18, 24 months post-radiotherapy
Change from baseline in prostate cancer-specific quality of life (EORTC QLQ-PR25)
Time Frame: Baseline, 1, 3, 6, 12, 18, and 24 months post-radiotherapy

Change from baseline in prostate cancer-specific quality of life domains assessed using the EORTC QLQ-PR25 questionnaire.

Score range: 0-100 Higher scores indicate worse symptoms.
Baseline, 1, 3, 6, 12, 18, and 24 months post-radiotherapy
Change from baseline in urinary symptoms (IPSS)
Time Frame: Baseline, 1, 3, 6, 12, 18, and 24 months post-radiotherapy

Change from baseline in urinary symptoms assessed using the International Prostate Symptom Score (IPSS).

Score range: 0-35 Higher scores indicate worse urinary symptoms.
Baseline, 1, 3, 6, 12, 18, and 24 months post-radiotherapy

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Clinique Sainte Clotilde

Investigators

  • Study Chair: Youssef Slama, Clinique sainte Clotilde

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

November 18, 2025

Primary Completion (Estimated)

March 1, 2029

Study Completion (Estimated)

May 1, 2029

Study Registration Dates

First Submitted

December 15, 2025

First Submitted That Met QC Criteria

January 8, 2026

First Posted (Actual)

January 15, 2026

Study Record Updates

Last Update Posted (Actual)

January 15, 2026

Last Update Submitted That Met QC Criteria

January 8, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2025-A00339-40

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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