SABR Treatments for Prostate Cancer

(iSMART Trial)

Overseen By Danny Vesprini, MD

Age: 18+

Sex: Male

Trial Phase: Academic

Sponsor: Sunnybrook Health Sciences Centre

Must not be taking: Androgens, Anticoagulants, Immunosuppressives

Disqualifiers: Prior pelvic radiotherapy, Bleeding diathesis, Large prostate, Inflammatory bowel disease, 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: 3

Duration: 2-5 weeks

144 Participants Needed

Trial Summary

Do I need to stop my current medications for the trial?

The trial requires you to stop taking anticoagulation and immunosuppressive medications. If you are on these, you may need to discontinue them to participate.

What data supports the idea that SABR Treatments for Prostate Cancer is an effective treatment?

The available research shows that SABR treatments for prostate cancer are effective, especially for low- and intermediate-risk patients. Two large studies compared SABR to traditional radiation methods and found it to be a promising option. SABR is also well-tolerated and less costly, which could make it more accessible. However, for high-risk patients, more research is needed before it can be widely recommended outside of clinical trials. ^{1 2 3 4 5}

What safety data is available for SABR treatment in prostate cancer?

SABR, also known as SBRT or UHRT, has been studied for its safety and efficacy in prostate cancer treatment. For low- and intermediate-risk patients, it has been compared to conventional radiotherapy in large randomized studies, showing it to be feasible and well-tolerated with careful planning. However, for high-risk patients, there is insufficient data to recommend its use outside clinical trials. Studies have also reviewed toxicity and quality of life, indicating that SABR is increasingly adopted due to its cost-effectiveness and potential to increase system capacity. ^{1 2 5 6 7}

Is the treatment Stereotactic Ablative Body Radiation (SABR) promising for prostate cancer?

Yes, SABR is a promising treatment for prostate cancer, especially for low and intermediate-risk patients. It uses high precision to target cancer with fewer sessions, which can save time and money for both patients and healthcare systems. It is becoming a standard treatment in some places due to its effectiveness and efficiency. ^{1 3 4 8 9}

What is the purpose of this trial?

Prostate Stereotactic ablative body radiotherapy (SABR) is an established technique that delivers radiation in a non-invasive approach for men with prostate cancer. The treatment regimen is given in total of 5 fractions with one treatment per day at every other day or weekly sessions. Ultra-hypofractionated radiotherapy (UHRT) is an emerging monotherapy for localized prostate cancer however, several trials have observed demonstrating superior biochemical control of a two-fraction (HDR) over single-fraction approach. The study aims to compare an experimental shorter course of prostate ultra-hypofractionated radiotherapy (UHRT) that will deliver what is expected to be an equivalent amount of radiation as given in the standard 5 treatment regimen. UHRT is given in 2 treatments with one treatment a week for 2 consecutive weeks.

Research Team

Danny Vesprini, MD

Principal Investigator

Sunnybrook Health Sciences Centre

Eligibility Criteria

Men with confirmed prostate adenocarcinoma, classified as low risk (T1-T2b, grade group 1, PSA <10 ng/ml) or favorable intermediate risk. Intermediate risk is defined by only one factor: cT2c, grade group 2, PSA between 10-20 ng/ml; or Grade group 3 with PSA <20 and <cT2c where pattern 4/5 is less than 10%.

Inclusion Criteria

My prostate cancer is considered favorable risk with limited intermediate risk factors.

My prostate cancer is early stage, low grade, and my PSA is under 10.

My prostate cancer diagnosis was confirmed through a biopsy.

Exclusion Criteria

I am receiving or will receive hormone therapy for my cancer.

My prostate is larger than 90cm3 according to scans.

I am not taking any immunosuppressive medications.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive either two weekly fractions of 13.5 Gy or five every other day fractions of 8 Gy of stereotactic ablative body radiotherapy (SABR)

2-5 weeks

2-5 visits (in-person)

Follow-up

Participants are monitored for safety, effectiveness, and quality of life changes after treatment

5 years

Visits at week 1, 4, 13; month 6; and every 6 months for 5 years

Treatment Details

Interventions

• Stereotactic Ablative Body Radiation

Trial Overview The trial compares two different schedules of delivering radiation for prostate cancer treatment. One uses the standard five sessions of SABR while the experimental approach condenses this into just two treatments a week apart to see if it's equally effective.

Participant Groups

Group I: Arm 1 Experimental Treatment 1 Intervention

Two weekly fractions of 13.5 Gy

Group II: Arm 2 Active Control 1 Intervention

Five every other day fractions of 8 Gy

Stereotactic Ablative Body Radiation is already approved in United States, European Union, Canada, Japan for the following indications:

Approved in United States as Stereotactic Body Radiation Therapy (SBRT) for:

• Prostate cancer
• Lung cancer
• Liver cancer
• Spine cancer
• Pancreatic cancer
• Kidney cancer

Approved in European Union as Stereotactic Ablative Radiotherapy (SABR) for:

• Prostate cancer
• Lung cancer
• Liver cancer
• Spine cancer
• Pancreatic cancer
• Kidney cancer

Approved in Canada as Stereotactic Body Radiation Therapy (SBRT) for:

• Prostate cancer
• Lung cancer
• Liver cancer
• Spine cancer
• Pancreatic cancer
• Kidney cancer

Approved in Japan as Stereotactic Ablative Radiotherapy (SABR) for:

• Prostate cancer
• Lung cancer
• Liver cancer
• Spine cancer
• Pancreatic cancer
• Kidney cancer

Who Is Running the Clinical Trial?

Sunnybrook Health Sciences Centre

Lead Sponsor

Trials

693

Recruited

1,569,000+

Prostate Cure Foundation

Collaborator

Trials

2

Recruited

220+

Findings from Research

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]

A systematic review of studies on stereotactic body radiation therapy (SBRT) for prostate cancer found that most patients experienced mild to moderate side effects, with severe toxicity occurring in less than 3% of cases, indicating that SBRT is generally well tolerated.

The review identified important dosimetric factors that influence toxicity, such as recommended dose constraints for the bladder, urethra, and rectum, which can help optimize treatment safety and effectiveness.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Prostate Stereotactic Body Radiation Therapy: An Overview of Toxicity and Dose Response. Wang, K., Mavroidis, P., Royce, TJ., et al.[2022]

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]

In a study involving 51 prostate cancer patients treated with stereotactic body radiotherapy (SBRT), the treatment showed promising outcomes with manageable toxicity levels, as no patients experienced severe (grade 3+) side effects during the initial follow-up period.

The median follow-up of 14.5 months revealed a low prostate-specific antigen level of 1.3 ng/ml at 13-18 months post-treatment, indicating effective disease control in this cohort.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Prostate stereotactic body radiotherapy—first UK experience. Tree, AC., Ostler, P., Hoskin, P., et al.[2022]

In a study of 66 prostate cancer patients treated with ultra-hypofractionated stereotactic body radiation therapy (SBRT), the treatment demonstrated excellent biochemical control, with a 2-year freedom from biochemical failure (FFBF) rate of 88.4%.

The treatment was associated with low toxicity, as no patients experienced severe (grade ≥3) genitourinary toxicity, and only 13.6% experienced grade 2 toxicities, indicating that SBRT is a safe option for postoperative prostate cancer management.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Treatment outcomes of postoperative ultra-hypofractionated stereotactic body radiotherapy in prostate cancer. Ozyigit, G., Onal, C., Beduk Esen, CS., et al.[2023]

In a study of 205 prostate cancer patients treated with stereotactic body radiation therapy (SBRT), 99% completed the treatment without severe acute side effects, indicating that this method is safe and well-tolerated.

The most common acute side effects were mild to moderate, with 50.7% experiencing grade II genitourinary issues and 31.7% experiencing grade I gastrointestinal issues, but no patients had severe (grade ≥ 4) toxicity.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Acute side effects after definitive stereotactic body radiation therapy (SBRT) for patients with clinically localized or locally advanced prostate cancer: a single institution prospective study. Jorgo, K., Polgar, C., Stelczer, G., et al.[2022]

In a study of 558 men with localized prostate cancer, there was no significant difference in overall survival between those treated with stereotactic body radiotherapy (SBRT) plus androgen deprivation therapy (ADT) and those receiving conventional external beam radiotherapy (EBRT) plus ADT, after a median follow-up of 74 months.

The findings support recent NCCN guidelines that classify SBRT as a non-preferred option for higher-risk prostate cancer, indicating that both treatment modalities have similar efficacy in terms of survival outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Stereotactic body radiotherapy versus conventional/moderate fractionated radiation therapy with androgen deprivation therapy for unfavorable risk prostate cancer. Patel, SA., Switchenko, JM., Fischer-Valuck, B., et al.[2021]

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]

Stereotactic body radiation therapy (SBRT) for localized prostate cancer showed a high two-year biochemical relapse-free survival rate of 99%, indicating its efficacy in controlling the disease.

The treatment was well tolerated, with low rates of gastrointestinal (1%) and genitourinary (31%) toxicities, and most patients who were sexually potent before treatment maintained their potency two years later.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Stereotactic body radiation therapy (SBRT) for clinically localized prostate cancer: the Georgetown University experience. Chen, LN., Suy, S., Uhm, S., et al.[2022]

References

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

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

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

Prostate Stereotactic Body Radiation Therapy: An Overview of Toxicity and Dose Response. [2022]

3. Switzerland pubmed.ncbi.nlm.nih.gov

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

4. England pubmed.ncbi.nlm.nih.gov

Prostate stereotactic body radiotherapy—first UK experience. [2022]

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

Treatment outcomes of postoperative ultra-hypofractionated stereotactic body radiotherapy in prostate cancer. [2023]

6. Poland pubmed.ncbi.nlm.nih.gov

Acute side effects after definitive stereotactic body radiation therapy (SBRT) for patients with clinically localized or locally advanced prostate cancer: a single institution prospective study. [2022]

7. England pubmed.ncbi.nlm.nih.gov

Stereotactic body radiotherapy versus conventional/moderate fractionated radiation therapy with androgen deprivation therapy for unfavorable risk prostate cancer. [2021]

8. Switzerland pubmed.ncbi.nlm.nih.gov

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

9. England pubmed.ncbi.nlm.nih.gov

Stereotactic body radiation therapy (SBRT) for clinically localized prostate cancer: the Georgetown University experience. [2022]