SABR for Prostate Cancer

Overseen By Urban Emmenegger, MD

Age: 18+

Sex: Male

Trial Phase: Academic

Sponsor: Sunnybrook Health Sciences Centre

Must be taking: Abiraterone

Disqualifiers: Opioid therapy, Cytotoxic chemotherapy, others

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

Approved in 4 Jurisdictions This treatment is already approved in other countries

Compensation: Varies

Number of Visits: 1

Duration: 5-10 weeks

30 Participants Needed

Trial Summary

What is the purpose of this trial?

There is increasing worldwide interest in exploring stereotactic ablative body radiotherapy (SABR) for treating metastases in men with prostate cancer, including for the treatment of oligoprogressive metastases. The latter applies to a situation whereby patients with widespread metastases undergoing systemic therapy present with a solitary or a few metastatic tumors that progress, while all other metastases are stable or responding. The usual practice would be to change systemic therapy at this point, but another approach is to locally ablate the "rogue" metastases and continue the same systemic therapy. SABR used in this scenario may delay the need to switch to another line of systemic therapy and improve progression-free survival while patients stay on the same systemic therapy.

Will I have to stop taking my current medications?

The trial requires that participants continue taking abiraterone, a medication for prostate cancer, while undergoing the treatment.

What data supports the effectiveness of the treatment Stereotactic Body Radiation Therapy (SABR) for prostate cancer?

Stereotactic Body Radiation Therapy (SABR) is a promising treatment for prostate cancer, showing similar effectiveness to brachytherapy, a well-established treatment, with potentially fewer side effects. It is well-tolerated, feasible, and may delay further treatment in cases of oligometastatic prostate cancer, although more research is needed to confirm its benefits. ^{1 2 3 4 5}

Is SABR generally safe for treating prostate cancer?

SABR (Stereotactic Ablative Radiotherapy) has been used for prostate cancer and other conditions, showing promising results in controlling tumors. However, some serious complications have been reported, so strategies to reduce these risks are important. ^{4 5 6 7 8}

How is the treatment SABR different from other treatments for prostate cancer?

Stereotactic Body Radiation Therapy (SABR) is a unique treatment for prostate cancer because it delivers high doses of radiation precisely to the cancer in fewer sessions, minimizing damage to surrounding healthy tissue. This non-invasive method is similar in effectiveness to brachytherapy but with potentially fewer side effects and is more resource-efficient, making it a promising option for low and intermediate-risk prostate cancer. ^{2 4 5 7 9}

Eligibility Criteria

This trial is for men with prostate cancer that's spread but mostly under control while on abiraterone, except for up to 5 'rogue' tumors getting worse. They should be fairly active (ECOG 0-1), have a confirmed diagnosis, and all progressing spots can be targeted by SABR. Men with spinal cord compression, recent cancers besides skin or in-situ types, or severe symptoms needing immediate other treatments can't join.

Inclusion Criteria

My prostate cancer has spread and is not responding to hormone therapy.

I am fully active or can carry out light work.

I am currently being treated with abiraterone.

Exclusion Criteria

I have not had cancer, except for non-dangerous skin cancer or in-situ cancer, in the last 5 years.

My cancer has worsened, needing strong painkillers, immediate chemotherapy, or has greatly affected my daily activities.

I have been diagnosed with spinal cord compression.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive stereotactic ablative body radiotherapy (SABR) for oligoprogressive metastatic sites while continuing abiraterone therapy

5-10 weeks

Multiple visits for SABR sessions

Follow-up

Participants are monitored for safety, progression-free survival, and quality of life after SABR treatment

24 months

Regular visits at 1, 3, 6, 9, and 12 months, then as needed

Long-term follow-up

Participants are monitored for overall survival and time to changing systemic therapy

36 months

Treatment Details

Interventions

• Stereotactic Body Radiation Therapy (SABR)

Trial Overview The study tests if Stereotactic Ablative Radiation Therapy (SABR) can target few worsening metastases in prostate cancer patients resistant to abiraterone without changing their current systemic therapy. The goal is to see if this approach delays the need for new systemic treatments and helps control the disease longer.

Participant Groups

Group I: Treatment Arm Experimental Treatment 1 Intervention

All metastases that fulfill the definition of oligoprogression seen on conventional imaging will be treated with standard SABR dose fractionation schemes routinely used at Sunnybrook Odette Cancer Centre. The prostate (if present and not previously treated) will be treated to a dose of 35 Gy in 5 fractions. Non-spine bone metastases will be treated to a dose of 30-40 Gy in 5 fractions. Spine metastases will be treated to a dose of 24 Gy in 2-3 fractions or 30-40 Gy in 5 fractions. Involved lymphadenopathy will be treated to a dose of 30-40 Gy in 5 fractions. Similarly, brain, lung, liver, and adrenal metastases will be treated with standard Sunnybrook SABR doses. Patients will remain on abiraterone during and after SABR treatments.

Stereotactic Body Radiation Therapy (SABR) is already approved in United States, European Union, Canada for the following indications:

Approved in United States as Stereotactic Body Radiation Therapy for:

• Prostate cancer
• Lung cancer
• Kidney cancer
• Bone metastases
• Liver metastases

Approved in European Union as Stereotactic Ablative Radiotherapy for:

• Prostate cancer
• Lung cancer
• Kidney cancer
• Bone metastases
• Liver metastases

Approved in Canada as Stereotactic Ablative Radiotherapy for:

• Prostate cancer
• Lung cancer
• Kidney cancer
• Bone metastases
• Liver metastases

Who Is Running the Clinical Trial?

Sunnybrook Health Sciences Centre

Lead Sponsor

Trials

693

Recruited

1,569,000+

Findings from Research

In a study of 152 men with intermediate risk prostate cancer, weekly stereotactic ablative radiotherapy (SABR) resulted in better short-term bowel and urinary quality of life compared to every other day treatment, but there were no significant differences in late toxicity or long-term quality of life outcomes after 62 months.

Both treatment regimens showed similar rates of biochemical failure and overall survival, indicating that while weekly SABR may reduce acute side effects, it does not compromise long-term efficacy or safety.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Accelerating prostate stereotactic ablative body radiotherapy: Efficacy and toxicity of a randomized phase II study of 11 versus 29 days overall treatment time (PATRIOT). Alayed, Y., Quon, H., Ong, A., et al.[2021]

Stereotactic ablative body radiation (SABR) is a promising non-invasive treatment for localized prostate cancer, showing similar efficacy to brachytherapy in terms of disease control and lower side effects, making it a potentially safer option.

SABR is also more cost-effective and resource-efficient compared to traditional radiation techniques, but further well-powered studies are needed to confirm its benefits before it can be considered standard care, especially for patients with metastatic disease.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Stereotactic ablative body radiotherapy in patients with prostate cancer. Loblaw, A., Liu, S., Cheung, P.[2023]

Stereotactic ablative radiotherapy (SABR) has been shown to be feasible and well tolerated for low- and intermediate-risk prostate cancer patients, with promising results from large randomized studies comparing it to conventional treatments.

While SABR shows potential benefits and cost-effectiveness, there is currently insufficient data to recommend its use for high-risk prostate cancer patients outside of clinical trials.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Stereotactic Ablative Body Radiotherapy for Intermediate- or High-Risk Prostate Cancer. Loblaw, A.[2021]

In a study of 84 low-risk prostate cancer patients treated with Stereotactic Ablative Body Radiotherapy (SABR), long-term quality of life (QOL) outcomes were generally positive, with a median follow-up of 50.8 months, although some patients reported declines in urinary (17.9%), bowel (26.2%), and sexual (37.5%) QOL domains.

Dosimetric factors such as rectal D1cc and penile bulb V35 were identified as significant predictors of worse QOL, highlighting the importance of adhering to strict dosimetric constraints to minimize side effects from treatment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Dosimetric and patient correlates of quality of life after prostate stereotactic ablative radiotherapy. Elias, E., Helou, J., Zhang, L., et al.[2018]

A single session of stereotactic ablative body radiotherapy (SABR) for oligometastatic prostate cancer was found to be feasible and safe, with only one significant adverse event (a vertebral fracture) reported among 33 patients over a 2-year follow-up period.

The treatment resulted in high local progression-free survival rates of 97% at 1 year and 93% at 2 years, with nearly half of the patients (48%) avoiding the need for androgen deprivation therapy at the 2-year mark, indicating effective disease control and maintained quality of life.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Stereotactic Abative Body Radiotherapy (SABR) for Oligometastatic Prostate Cancer: A Prospective Clinical Trial. Siva, S., Bressel, M., Murphy, DG., et al.[2022]

Stereotactic ablative radiation (SAbR) at a dose of 45 Gy in 5 fractions shows a promising safety profile for treating localized prostate cancer, with acute urinary and gastrointestinal toxicity rates of 20.4% and 7.3%, respectively, and low rates of late toxicity after 2 years.

The treatment demonstrated excellent efficacy, with a biochemical failure-free survival rate of 100% at 1 year and 98.7% at 2 years, indicating strong disease control outcomes for patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Dose-Intensified Stereotactic Ablative Radiation for Localized Prostate Cancer. Chen, L., Gannavarapu, BS., Desai, NB., et al.[2022]

CyberKnife stereotactic ablative radiotherapy (SABR) for treating intermediate- to very-high-risk prostate cancer showed a high 3-year biochemical relapse-free survival rate of 90.2%, indicating its efficacy in managing this condition.

The treatment was well-tolerated, with no patients experiencing severe toxicity (≥ grade 3), and only mild genitourinary and gastrointestinal side effects were reported, suggesting a favorable safety profile.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Stereotactic ablative radiotherapy with CyberKnife in the treatment of locally advanced prostate cancer: preliminary results. Fan, CY., Chao, HL., Huang, WY., et al.[2017]

Stereotactic ablative radiotherapy (SABR) has rapidly expanded in clinical use for treating various primary and metastatic tumors, demonstrating promising results in tumor control.

Despite its effectiveness, SABR can lead to serious complications, highlighting the need for strategies to reduce these risks and improve the safety of the treatment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Serious complications associated with stereotactic ablative radiotherapy and strategies to mitigate the risk. Lo, SS., Sahgal, A., Chang, EL., et al.[2018]

Stereotactic ablative body radiotherapy (SABR) is an advanced treatment that delivers high doses of radiation in fewer sessions while protecting surrounding healthy tissues, making it effective for small tumors in various locations, including the prostate.

SABR is becoming a standard treatment for low and intermediate-risk prostate cancer, supported by research from Sunnybrook and the US prostate SABR consortium, highlighting its efficacy in improving patient outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Evolution of hypofractionated accelerated radiotherapy for prostate cancer - the sunnybrook experience. Musunuru, HB., Cheung, P., Loblaw, A.[2022]

References

1. Ireland pubmed.ncbi.nlm.nih.gov

Accelerating prostate stereotactic ablative body radiotherapy: Efficacy and toxicity of a randomized phase II study of 11 versus 29 days overall treatment time (PATRIOT). [2021]

2. China pubmed.ncbi.nlm.nih.gov

Stereotactic ablative body radiotherapy in patients with prostate cancer. [2023]

3. United States pubmed.ncbi.nlm.nih.gov

Stereotactic Ablative Body Radiotherapy for Intermediate- or High-Risk Prostate Cancer. [2021]

4. Ireland pubmed.ncbi.nlm.nih.gov

Dosimetric and patient correlates of quality of life after prostate stereotactic ablative radiotherapy. [2018]

5. Switzerland pubmed.ncbi.nlm.nih.gov

Stereotactic Abative Body Radiotherapy (SABR) for Oligometastatic Prostate Cancer: A Prospective Clinical Trial. [2022]

6. Switzerland pubmed.ncbi.nlm.nih.gov

Dose-Intensified Stereotactic Ablative Radiation for Localized Prostate Cancer. [2022]

7. United States pubmed.ncbi.nlm.nih.gov

Stereotactic ablative radiotherapy with CyberKnife in the treatment of locally advanced prostate cancer: preliminary results. [2017]

8. England pubmed.ncbi.nlm.nih.gov

Serious complications associated with stereotactic ablative radiotherapy and strategies to mitigate the risk. [2018]

9. Switzerland pubmed.ncbi.nlm.nih.gov

Evolution of hypofractionated accelerated radiotherapy for prostate cancer - the sunnybrook experience. [2022]