Local Ablative Therapy for Prostate Cancer

(PLATON Trial)

Not currently recruiting at 20 trial locations

Overseen By Wendy Parulekar

Age: 18+

Sex: Male

Trial Phase: Academic

Sponsor: Canadian Cancer Trials Group

Must be taking: Zoladex

Disqualifiers: Castration resistant prostate cancer, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Approved in 2 Jurisdictions This treatment is already approved in other countries

Compensation: Varies

Number of Visits: Unknown

Duration: 6 years

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores whether adding local ablative therapy, such as targeted radiation or surgery, to standard treatments can improve outcomes for prostate cancer patients. Researchers aim to determine if treating all cancer sites in this manner is more effective than using only the usual treatments. Men with Stage IV prostate cancer, who have up to five metastases and whose tumors can be treated with radiation or surgery, might be suitable candidates for this trial. As an unphased trial, this study allows patients to contribute to innovative research that could enhance future treatment options.

Will I have to stop taking my current medications?

The trial protocol does not specify if you need to stop taking your current medications. However, it does require that Zoladex (a hormone therapy) be started within a specific timeframe related to the trial.

What prior data suggests that ablative therapy is safe for prostate cancer treatment?

Research has shown that ablative radiation therapy for prostate cancer is generally safe and well-tolerated. One study found that Stereotactic Ablative Radiotherapy (SABR) is practical and causes few additional side effects, meaning patients experienced minimal harmful effects. Another study demonstrated that the treatment effectively controlled the cancer locally, with high survival rates over ten years for patients with low and intermediate risk. Overall, evidence suggests that ablative radiation therapy is a promising and safe option for prostate cancer patients. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about this trial because it explores the combination of local ablative therapy with standard systemic treatments for prostate cancer. Unlike typical treatments that focus solely on systemic therapy to manage the disease, this approach targets and destroys cancer cells at all disease sites, including the primary tumor in the prostate. This could potentially improve treatment outcomes by directly reducing the tumor burden in patients with low-volume metastatic disease. By integrating ablative therapy with existing systemic options, researchers hope to enhance the effectiveness and precision of prostate cancer treatment.

What evidence suggests that this trial's treatments could be effective for prostate cancer?

Research has shown that treatments like radiation, known as ablative therapy, effectively treat prostate cancer. In this trial, one group will receive standard systemic therapy combined with ablative therapy to all disease sites, including the untreated prostate primary. Studies have found that patients who received stereotactic ablative body radiotherapy (SABR) experienced a longer period without cancer progression. Many tolerate SABR well, and it typically doesn't cause severe side effects. Specifically, one study found that after eight years, up to 94.6% of patients with lower-risk prostate cancer showed no signs of cancer progression. These findings suggest that adding ablative therapy to standard treatments can enhance their effectiveness for prostate cancer patients. ^{2 6 7 8 9}

Who Is on the Research Team?

Patrick CF Cheung

Principal Investigator

Odette Cancer Centre, Sunnybrook Health Science Centre, Toronto, ON Canada

M. Tamim Niazi

Principal Investigator

The Jewish General Hospital, Montreal, QC Canada

Are You a Good Fit for This Trial?

Men over 18 with hormone-sensitive prostate cancer that has spread to no more than five places and hasn't become resistant to hormonal therapy. They should be in good physical condition, able to fill out questionnaires in English or French, and willing to use effective contraception. Those who've had certain previous treatments or have brain metastases can't join.

Inclusion Criteria

Bone scan within 42 days of randomization

My prostate cancer is adenocarcinoma without any small cell cancer.

I started or will start Zoladex within 12 weeks around my trial entry.

Exclusion Criteria

My prostate cancer has spread to pelvic lymph nodes only and hasn't been treated before.

I stopped my hormone therapy for cancer more than a year ago and it lasted less than 3 years.

My prostate cancer is growing despite low testosterone levels.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive standard systemic therapy with or without ablative therapy (SBRT or surgery) to all sites of disease

6 years

Follow-up

Participants are monitored for safety and effectiveness after treatment

6 years

What Are the Treatments Tested in This Trial?

Interventions

• Ablative Radiation Therapy
• Standard of care

Trial Overview The trial is testing whether adding ablative therapy (targeted radiation or surgery) to standard care improves outcomes for men with limited-spread prostate cancer compared to standard care alone. Participants will be randomly assigned to one of the two approaches.

How Is the Trial Designed?

Group I: Arm 2 (standard systemic therapy + ablative therapy)) Experimental Treatment 2 Interventions

Local Ablative therapy to all sites of disease (including untreated prostate primary) \+ Standard systemic therapy

Group II: Arm 1 (standard of care) Active Control 1 Intervention

Standard systemic therapy \+ Ablative therapy to untreated prostate primary for patients with low volume metastatic disease burden

Standard of care is already approved in United States, European Union for the following indications:

Approved in United States as Botulinum toxin injections for:

• Focal dystonia
• Segmental dystonia
• Cervical dystonia
• Blepharospasm

Approved in European Union as Botulinum toxin injections for:

• Primary cranial dystonia
• Cervical dystonia
• Writing dystonia

Approved in United States as Deep Brain Stimulation for:

• Primary generalized dystonia
• Cervical dystonia

Approved in European Union as Deep Brain Stimulation for:

• Primary generalized dystonia
• Cervical dystonia

Who Is Running the Clinical Trial?

Canadian Cancer Trials Group

Lead Sponsor

Trials

135

Recruited

70,300+

TerSera Therapeutics LLC

Industry Sponsor

Trials

11

Recruited

1,300+

Canadian Cancer Society (CCS)

Collaborator

Trials

84

Recruited

42,100+

Published Research Related to This Trial

Recent advancements in radiation therapy techniques, such as Stereotactic Body Radiotherapy (SBRT), proton beam radiation, and high-dose-rate (HDR) brachytherapy, show promise in effectively treating prostate cancer while minimizing toxicity.

For high-risk prostate cancer, these new radiation modalities are often combined with regional radiation therapy to ensure comprehensive treatment, while non-radiation therapies like cryoablation and high-intensity focused ultrasound are still considered experimental for this patient group.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Emerging Technologies and Techniques in Radiation Therapy. Magnuson, WJ., Mahal, A., Yu, JB.[2018]

Minimally invasive local ablative therapies, such as cryotherapy and high-intensity focused ultrasound, offer an alternative to traditional radical therapies for men with localized prostate cancer, providing a balance between treatment and quality of life.

These therapies are generally well tolerated with lower side effects compared to surgery or radiation, but their long-term effectiveness in controlling cancer is still uncertain.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Minimally invasive ablative therapies for definitive treatment of localized prostate cancer in the primary setting. Lee, EW., Huang, WC.[2021]

Minimally-invasive ablative therapies like cryotherapy, high intensity focused ultrasound (HIFU), and photodynamic therapy provide effective early cancer control for localized prostate cancer while minimizing side effects, particularly genitourinary morbidity.

These treatments allow for focal therapy, targeting only the cancerous lesions in the prostate, which offers a less aggressive alternative compared to radical therapies and active surveillance.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Minimally-invasive technologies in uro-oncology: the role of cryotherapy, HIFU and photodynamic therapy in whole gland and focal therapy of localised prostate cancer. Ahmed, HU., Moore, C., Emberton, M.[2021]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC6043737/

Stereotactic ablative body radiotherapy in patients with ... With a median follow-up of 84 months, the 8-year biochemical disease-free survival (bDFS) was 94.6%, 94.3% and 65.0% for patients with low-, intermediate- and ...

2. redjournal.org redjournal.org/article/S0360-3016(25)01631-1/fulltext

Two-Year Clinical Outcomes Following Ablative ... 97% of patients received ADT for a median duration of 12 months (6–24). After a median follow-up of 24 months (18–42), no ≥ grade 3 toxicity was ...

3. sciencedirect.com sciencedirect.com/science/article/abs/pii/S1879850025001511

Clinician- and Patient-Reported Outcomes of Stereotactic ... Conclusions. SABR delivering 40 Gy in 5 fractions is feasible and well-tolerated for high-risk prostate cancer, with minimal additional toxicity ...

4. jamanetwork.com jamanetwork.com/journals/jamaoncology/fullarticle/2763312

Outcomes of Observation vs Stereotactic Ablative ... Treatment with SABR improved median progression-free survival (not reached vs 5.8 months; hazard ratio, 0.30; 95% CI, 0.11-0.81; P = .002).

5. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/34740477/

Comparative Effectiveness Analyses of Salvage ... The aim of this study was to compare oncological and functional outcomes after salvage robot-assisted radical prostatectomy (SRARP) and salvage radiotherapy ( ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC7528218/

Comparison of outcomes and toxicities among radiation ... SBRT had promising rates of BF, with shorter follow-up (5-year FFBF of >90% for low-risk patients). Similarly, BT (5-year FFBF for low-, intermediate-, and high ...

7. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC7761604/

Ablative Radiotherapy in Prostate Cancer: Stereotactic Body ... Local control at 10 years was excellent at 99.7% and 98.9% for low- and intermediate-risk patients, with 10-year bPFS of 98.9% and 95.2%, ...

8. jamanetwork.com jamanetwork.com/journals/jamaoncology/fullarticle/2773455

Safety and Survival Rates Associated With Ablative ... Updated findings noted 5-year androgen deprivation therapy–free survival rates of 34% for the metastasis-directed therapy and 8% for the ...

9. sciencedirect.com sciencedirect.com/science/article/pii/S2588931125000860

Long-term Oncological Outcomes in the Phase 2 PATRIOT ... This study suggests no significant differences in long-term cancer outcomes between EOD and QW schedules for five-fraction prostate SABR.