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Prostate Cancer MetastaticPLATONNCT03784755

Local Ablative Therapy For Hormone Sensitive Oligometastatic Prostate Cancer

A study testing Ablative Radiation Therapy in people with Prostate Cancer Metastatic, run by Canadian Cancer Trials Group at 18 sites in Canada.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial summary

The purpose of this study is to compare the effects of ablative therapy (radiation or surgery) to all sites of disease combined with standard treatments on prostate cancer, compared to the standard or usual treatments used to treat this disease. Read more about this study

Who is it for?
Ages 18 years and older, men only
Conditions the study is for
Prostate Cancer Metastatic
What is being tested?
Ablative Radiation Therapy
Type of treatment
Surgery or procedure
Could I receive a placebo?
No, everyone receives an active treatment
How many people
409 participants
Where
18 sitesCanada
Study dates
15 Nov 2019to 30 Jul 2033
Phase
Interventional
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • Men only
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Histologic diagnosis/confirmation of prostate adenocarcinoma and no evidence of small cell cancer.
  • Stage IV at presentation or relapse after curative intent therapy, classification per AJCC 8th edition: M1 disease with ≤ 5 metastases
  • ≤ 3 metastases in any non-bone organ system
  • Zoladex must commence within 12 weeks prior to randomization or within 12 weeks after randomization.
  • Radiology (CT/MRI chest/abdomen/pelvis) within 42 days of randomization
  • Bone scan within 42 days of randomization
Show all 18Show fewer
  • All tumours (Primary prostate and metastases) must be amenable to local ablative therapy (radiation and/or surgery).
  • Age ≥ 18
  • ECOG performance 0-2
  • Patient is able (i.e. sufficiently fluent) and willing to complete the quality of life and economics questionnaires in either English or French
  • Patient consent must be appropriately obtained in accordance with applicable local and regulatory requirements. Each patient must sign a consent form prior to enrollment in the trial to document their willingness to participate
  • Patients must be medically suitable for study treatments as assessed by the appropriate specialties: medical, radiation, and surgical
  • Patients with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen
  • Patients must be accessible for treatment and follow-up. Investigators must assure themselves the patients randomized on this trial will be available for complete documentation of the treatment, adverse events, and follow-up
  • In accordance with CCTG policy, ablative therapy to metastases is to begin within 6 weeks after patient randomization
  • Men of childbearing potential must have agreed to use a highly effective contraceptive method to prevent pregnancy while on study
  • Patient must consent to provision of, and Investigator must confirm location of and commit to obtain a representative formalin fixed paraffin block of tumour tissue in order that the specific correlative studies described in the protocol may be conducted. Where tissue exists but local centre regulations prohibit submission of blocks of tumour tissue, the approval of the CCTG must be sought prior to randomization of the first patient to allow cores (two 2 mm cores of tumour from the block) and slides (20 x 5 micron thick unstained slides) of representative tumour tissue to be substituted
  • Patient must consent to provision of samples of whole blood (for cfDNA) in order that the specific correlative studies described in the protocol may be conducted.

Who cannot join

  • Prior treatment with ADT in the neoadjuvant or adjuvant setting, unless treatment was discontinued ≥ 12 months prior to randomization AND total duration of treatment was ≤ 36 months (including expiry of last depot injection).
  • Previously diagnosed recurrent/metastatic disease which has been already treated with any systemic therapy or radiotherapy with palliative intent.
  • Castration resistant prostate cancer, defined as rising PSA (per PCWG3) or radiographic progression in the setting of castrate levels of serum testosterone (< 1.7 nmol/L).
  • Patients who present with de novo stage IV disease with pelvic lymphadenopathy as their only site of metastases (N1 M0), where the primary prostate has never been treated with curative intent prostate surgery or radiotherapy in the past.
  • Inability to treat all sites of disease with local ablative therapy
  • Patients with parenchymal brain metastases

Trial locations and contacts

18 sites in 1 country.

18 sites in 1 country

Canada18 sites

  • Royal Victoria Regional Health Centre

    Barrie, Ontario, L4M 6M2

  • Health Sciences North

    Greater Sudbury, Ontario, P3E 5J1

  • QEII Health Sciences Centre

    Halifax, Nova Scotia, B3H 1V7

  • Juravinski Cancer Centre at Hamilton Health Sciences

    Hamilton, Ontario, L8V 5C2

  • Kingston Health Sciences Centre

    Kingston, Ontario, K7L 2V7

  • Trillium Health Partners - Credit Valley Hospital

    Mississauga, Ontario, L5M 2N1

  • CIUSSS de l'Est-de-I'lle-de-Montreal

    Montreal, Quebec, H1T 2M4

  • CHUM-Centre Hospitalier de l'Universite de Montreal

    Montreal, Quebec, H2X 3E4

  • The Jewish General Hospital

    Montreal, Quebec, H3T 1E2

  • Ottawa Hospital Research Institute

    Ottawa, Ontario, K1H 8L6

  • Hotel-Dieu de Quebec

    Québec, Quebec, G1R 2J6

  • Allan Blair Cancer Centre

    Regina, Saskatchewan, S4T 7T1

  • Saskatoon Cancer Centre

    Saskatoon, Saskatchewan, S7N 4H4

  • Algoma District Cancer Program

    Sault Ste. Marie, Ontario, P6B 0A8

  • Odette Cancer Centre

    Toronto, Ontario, M4N 3M5

  • University Health Network

    Toronto, Ontario, M5G 2M9

  • BCCA - Victoria

    Victoria, British Columbia, V8R 6V5

  • CancerCare Manitoba

    Winnipeg, Manitoba, R3E 0V9

Other trials in Canada

About this study

Official title: A Randomized Phase III Trial of Local Ablative Therapy For Hormone Sensitive Oligometastatic Prostate Cancer [PLATON]

The purpose of this study is to compare the effects of ablative therapy (radiation or surgery) to all sites of disease combined with standard treatments on prostate cancer, compared to the standard or usual treatments used to treat this disease.

Read the detailed description

The standard or usual treatment for this disease is systemic therapy, which includes androgen deprivation therapy (ADT) with or without chemotherapy or hormone therapy. Additionally, for some patients with specific disease features, standard treatment may also include ablative treatment (radiation or surgery) of the prostate gland if this was not completed prior to enrolling into this study.

Ablative Therapy is a procedure used to destroy cancer cells and tissue. In this study Stereotactic Body Radiation Therapy (SBRT) or surgery will be used to destroy prostate cancer metastases. It is not clear if ablative therapy (SBRT or surgery) to all sites of disease used in combination with standard systemic therapy can offer better results than standard treatment alone.

Being tested
Ablative Radiation Therapy, Standard of care
Keywords
Oligometastatic Hormone

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Ablative Radiation TherapyRadiation

    Also called SBRT, Stereotactic External Beam Irradiation, Stereotactic Radiation Therapy, Stereotactic Radiotherapy

    Undergo stereotactic radiotherapy and/or surgery to all sites of disease (oligometastases and primary prostate if previously untreated).

  • Standard of careOther

    Patients continue to receive their current planned systemic therapy at the discretion of the treating physician

Study groups in NCT03784755
Study groupRoleWhat they receive
Arm 1 (standard of care)Active comparatorStandard systemic therapy + Ablative therapy to untreated prostate primary for patients with low volume metastatic disease burden
Receives: Other: Standard of care
Arm 2 (standard systemic therapy + ablative therapy))ExperimentalLocal Ablative therapy to all sites of disease (including untreated prostate primary) + Standard systemic therapy
Receives: Radiation: Ablative Radiation Therapy; Other: Standard of care

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Failure-free Survival

    defined as the time from randomization to the time of the first occurrence.

    Measured: 12 years

Secondary outcomes (9)

  1. Radiographic Progression-free Survival

    the comparison of these outcomes between the two treatment arms will be tested by the log-rank test

    Measured: 12 years

  2. Incidence of new metastases as first event

    the comparison of these outcomes between the two treatment arms will be tested by the log-rank test

    Measured: 12 years

  3. Overall Survival

    the comparison of these outcomes between the two treatment arms will be tested by the log-rank test

    Measured: 12 years

  4. Ablative treatment related adverse events (>/= grade 3) using CTCAE v5.0

    Measured: 12 years

  5. Quality of Life measured by EORTC QLQ-C30

    It consists of both multi-item scales and single item measures, including five functioning domains, a global quality of life domain, three symptom domains and six single items. For each domain or single item measure a linear transformation will be applied to standardize the raw score to range between 0 and 100

    Measured: 12 years

  6. Quality of Life measured by Bone Metastases module (BM22)

    The BM22 has 22 questions consisting of the 4 subscales (painful sites (PS) and pain characteristics (PC) on the symptom scale and functional interference (FI) and psychosocial aspects (PA) on the functional scale). Modules, relevant subscales will also be linear transformed to standardize the raw score to range between 0 and 100 in accordance with the EORTC scoring manuals.

    Measured: 12 years

  7. Quality of Life measured by prostate (PR25) questionnaire module

    has 25 questions in four domains (urinary, bowel, sexual, and hormonal). Modules, relevant subscales will also be linear transformed to standardize the raw score to range between 0 and 100 in accordance with the EORTC scoring manuals.

    Measured: 6 years

  8. Economic analysis measured by EQ-5D-5L

    The robustness of the model results will be assessed using one-way and multi-way sensitivity analyses. Major drivers of medical care costs, namely hospitalization, chemotherapy and survival, will be varied ± 20%, to examine the impact on the base-case incremental cost effectiveness ratios (ICERs). Bootstrapping and the development of a cost-effectiveness acceptability curve will also be conducted.

    Measured: 12 years

  9. Economic analysis by determining an incremental cost-effectiveness ratio reported as a difference in cost per FFS-year between the 2 arms

    Measured: 12 years

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted24 Dec 2018
  2. Study start15 Nov 2019
  3. Primary completion31 Dec 2032 (estimated)
  4. Study completion30 Jul 2033 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
None (open label)
Enrolment
409 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT03784755
Sponsor's protocol ID
PR20
Acronym
PLATON
Status last verified
Nov 2025
First submitted
19 Dec 2018
Last updated
27 Mar 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A study testing Ablative Radiation Therapy in people with Prostate Cancer Metastatic, run by Canadian Cancer Trials Group at 18 sites in Canada.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 18 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: under way, not looking for participants, as of the sponsor's last update on 27 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 18 sites in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Failure-free Survival (time frame: 12 years). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT03784755.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 27 Mar 2026.

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