Protons vs. Photons for High-risk Prostate Cancer

August 11, 2026 updated by: University of Aarhus

Lymph Node Radiation Therapy With Integrated Boost to Prostate for High-risk Prostate Cancer A Randomized Phase 3 Trial Comparing Photons vs. Protons

The purpose of this study is to assess late gastro-intestinal side-effects comparing proton therapy to photon therapy in high-risk prostate cancer patients receiving whole pelvic irradiation.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Detailed Description

Proton therapy (PT) is a radiation technique with possibility to spare normal pelvic organs: bladder, rectum and bowel for PC patients.

Most PC patients treated with PT receive PT to the prostate gland alone. With PT, we aim to examine PC patients in high risk with both lymph node and prostate treatment will experience less late side effects with PT compared to photon treatment.

The investigators propose a national open-labelled phase III randomized controlled trial (RCT) of proton therapy versus photon therapy of the prostate including the regional elective LN for localized/locally advanced prostate cancer patients combined with androgen deprivation therapy (ADT) aimed at 3 years. The investigators aim at reducing gastro-intestinal toxicity grad 2 more than 5 points, which is considered clinical significant, measured by mean Expanded Prostate Cancer Index Composite-26 (EPIC-26) bowel scores at 24 months and improve HRQOL. Secondary endpoints include morbidity, quality of life and survival data up to 10 years after treatment.

Update August 2026:

The primary endpoint has been updated. To consider a more meaningful clinical endpoint the investigators have decided to update the endpoint and look at a 10 points difference in EPIC-26 bowel score at 24 months follow-up instead of a 5 points difference. A new power-calculation was made based on the same assumptions and the total number of patients was changed from 400 to 102.

Study Type

Interventional

Enrollment (Estimated)

102

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 Locations

  • Denmark
    • Capital Region
      • Copenhagen, Capital Region, Denmark
        • Dept. of Oncology, Rigshospitalet, Denmark
      • Herlev, Capital Region, Denmark, DK-2730 Herlev
        • Department of Oncology, Copenhagen University Hospital Herlev
    • Central Region
      • Aarhus, Central Region, Denmark, 8200
        • Department of Oncology, Aarhus University Hospital
    • Region North
      • Aalborg, Region North, Denmark
        • Dept. of Oncology, Aalborg University Hospital
    • Region Sjælland
      • Næstved, Region Sjælland, Denmark
        • Dept. of Oncology, Zealand University Hospital, Denmark
    • Region South
      • Odense, Region South, Denmark, 5000
        • Department of Oncology, Odense University Hospital
      • Vejle, Region South, Denmark
        • Department of Oncology, Vejle Hospital, Denmark

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

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Histologically verified localized/locally advanced prostate cancer T1-3bN0-1M0 (TNM 8th edition). A clinical T4 is allowed if it is because of invasion into the bladder neck.
  • Adenocarcinoma (mixed histology allowed as long as the adenocarcinoma component comprise more than 50%)
  • Indication for elective lymph node irradiation
  • PSA < 100 ng/mL
  • Age ≥18 years
  • Performance status 0-1
  • Life expectancy ≥ 10 years
  • Able to understand and comply with the treatment protocol
  • No evidence of inflammatory bowel disease Ability to adhere to procedures for study and follow-up
  • Signed informed consent to participate in the study

Exclusion Criteria:

  • No previous treatment for prostate cancer
  • Hip-prostheses
  • Other metal devices in the pelvic region (except fiducials)
  • Previous major abdominal/rectal surgery
  • Any other malignancy the last five years except for basal or squamous cell skin cancer
  • Unable to understand patient information or comply with treatment and safety instructions
  • Unable to read and understand patient information due to cognitive disabilities or language (Danish).

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Proton therapy

Radiation: Proton Therapy 78 Gray (Gy) in 39 fractions with 56 Gy to the Pelvic Lymph Nodes (LN), 5 days a week.

Androgen Deprivation Therapy (ADT) for three years, starting 3 months before Proton Therapy.
Radiation: Proton therapy
Patients in the experimental arm will receive proton therapy within the same dose and fraction schedule as patients receiving photon therapy, which is standard treatment.
Active Comparator: Photon Therapy
Radiation: Photon Therapy 78 Gy in 39 fractions with 56 Gy to the pelvic LN, 5 days a week. ADT for three years, starting 3 months before Photon Therapy.
Radiation: Photon therapy
Patients in the photon arm will receive standard treatment with photon therapy.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Late gastrointestinal (GI) toxicity at year 2 compared to baseline using Expanded Prostate Cancer Index Composite-26 (EPIC-26)
Time Frame: 2 years
Patient Reported Outcome The investigators aim at reducing gastro-intestinal toxicity grad 2 more than 10 points, which is considered clinically significant.
2 years

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Late Genito-urinary (GU) and sexual toxicity ≥ 2 grade at year 2 and 5 compared to baseline (Common Terminology Criteria for Adverse Events (CTCAE) toxicity score (CTC_AE 5.0)
Time Frame: 5 years
Physician Assessed Toxicity Number of Participants With Treatment-Related Adverse events as assessed by CTCAE v5.0
5 years
Late GU and sexual toxicity at year 2, 5 and 10 compared to baseline (EPIC-26)
Time Frame: 10 years
Patient Reported Outcome using on-line questionnaire to assess this outcome measure
10 years
Late GI toxicity at year 5 compared to baseline (EPIC-26)
Time Frame: 5 years
Patient Reported Outcome using on-line questionnaire to assess this outcome measure.aim at reducing gastro-intestinal toxicity grad 2 more than 5 points, which is considered clinically significant, measured by mean points, which is considered clinically significant
5 years
Acute GI at start, at the end of therapy and week 12 compared to baseline (EPIC-26)
Time Frame: 12 weeks
EPIC-26
12 weeks
Acute GI at start, at the end of therapy and week 12 compared to baseline (CTC_AEv.5.0)
Time Frame: 12 weeks
Physician Assessed Toxicity
12 weeks
Acute GU toxicity at start, at the end of therapy and week 12 compared to baseline (EPIC-26)
Time Frame: 12 weeks
EPIC-26
12 weeks
Acute GU toxicity at start, at the end of therapy and week 12 compared to baseline (CTC_AE v.5.0)
Time Frame: 12 weeks
Physician Assessed Toxicity
12 weeks
General health related quality of life (QoL) at year 2, 5 and 10 compared to baseline (EORTC QLQ-C30)
Time Frame: 10 years
Patient Reported Outcome General health related quality of life (QoL) at year 2, 5 and 10 (EORTC QLQ-C30)
10 years
Biochemical progression free survival (BCR), (Phoenix criteria)
Time Frame: 10 years
blood test
10 years
Non-biochemical progression free survival (by imaging)
Time Frame: 10 years
Radiology assesments
10 years
Overall survival (OS)
Time Frame: 10 years
Follow up
10 years

Collaborators and Investigators

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

Sponsor

University of Aarhus

Collaborators

Odense University Hospital
Aarhus University Hospital
Rigshospitalet, Denmark
Aalborg University Hospital
Herlev and Gentofte Hospital
Sygehus Lillebaelt
Naestved Hospital

Investigators

  • Principal Investigator: Stine Elleberg Petersen, MD, Ph.D, Danish Centre for Particle Therapy, Aarhus University Hospital

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)

March 1, 2022

Primary Completion (Estimated)

December 1, 2028

Study Completion (Estimated)

December 1, 2038

Study Registration Dates

First Submitted

March 16, 2022

First Submitted That Met QC Criteria

April 21, 2022

First Posted (Actual)

April 28, 2022

Study Record Updates

Last Update Posted (Actual)

August 13, 2026

Last Update Submitted That Met QC Criteria

August 11, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 1-10-72-290-21

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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