Stereotactic Ablative Radiotherapy for Prostate Cancer

(DAPPER Trial)

Age: 18+

Sex: Male

Trial Phase: Academic

Sponsor: Mayo Clinic

Disqualifiers: Metastatic cancer, Chemotherapy, Radiation, 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: 6-8 weeks

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests a new radiation therapy for men who have had prostate removal due to cancer but still experience rising PSA levels, indicating potential cancer recurrence. The study evaluates whether this new method, Stereotactic Ablative Radiotherapy (SABR), which adjusts daily for precise targeting of the cancer area, is safe and effective. It aims to minimize radiation exposure to healthy tissue and reduce the number of treatments required. Men who have undergone prostate surgery and now face rising PSA levels might be suitable candidates for this trial. As an unphased trial, it offers patients the chance to contribute to innovative research that could enhance future prostate cancer treatments.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the trial coordinators or your doctor.

What prior data suggests that this radiation therapy technique is safe for prostate cancer patients?

Research has shown that stereotactic body radiation therapy (SBRT) is generally safe for treating prostate cancer. In one study, patients tolerated SBRT well, with only a small number experiencing significant side effects. Another study found that survival rates were similar to those with traditional radiation methods, without a large increase in side effects.

SBRT uses focused radiation to target cancer cells while protecting nearby healthy tissue. This method is promising because it delivers the right amount of radiation to the cancer while reducing exposure to the rest of the body. Although some side effects can occur, they are usually manageable and less severe than those seen with other types of radiation therapy. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about Stereotactic Body Radiation Therapy (SBRT) for prostate cancer because it offers a more precise and potentially less invasive approach than traditional radiation therapies. Unlike standard options that often require multiple sessions over several weeks, SBRT targets cancer cells with high-dose radiation in fewer sessions, potentially reducing treatment time and side effects. This trial explores daily adaptive online replanning, allowing for real-time adjustments that account for changes in the prostate and surrounding tissues, potentially increasing accuracy and effectiveness. This innovative approach could improve outcomes and quality of life for patients with prostate cancer.

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

Research has shown that stereotactic body radiation therapy (SBRT) works well for prostate cancer. In this trial, participants will receive SBRT with daily adaptive online replanning. Studies have found that SBRT can control cancer as effectively as standard radiation therapy but in less time. For example, one study using the CyberKnife System, a type of SBRT, demonstrated good results for patients with low- and intermediate-risk prostate cancer. Patients received focused treatment in just five sessions, much quicker than traditional radiation schedules. Besides being efficient, SBRT showed only small differences in survival rates compared to conventional methods, making it a safe and practical option for some patients. ^{2 3 6 7 8}

Who Is on the Research Team?

Bradley J. Stish

Principal Investigator

Mayo Clinic in Rochester

Are You a Good Fit for This Trial?

Men over 18 with prostate cancer who've had their prostate surgically removed and are now facing a rise in PSA levels, indicating potential remaining cancer. They must be able to handle daily activities with some limitations (ECOG PS ≤2), fill out questionnaires, give informed consent, and follow the study's check-up schedule. Men with untreated widespread cancer, recent chemotherapy, previous high-dose pelvic radiation, life expectancy under 5 years due to other diseases, decision-making impairments or non-adherence issues can't join.

Inclusion Criteria

Ability to complete questionnaire(s) by themselves or with assistance

Provide written informed consent

I can take care of myself but might not be able to do heavy physical work.

Exclusion Criteria

I have had surgery or needed treatment for issues with my bladder or urethra, but not including prostate removal.

I am a man who can father children and refuse to use birth control.

I have not had chemotherapy in the last 3 months.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

1 visit (in-person)

Treatment

Participants undergo daily adaptive online replanning for SBRT to the prostate fossa and/or pelvic lymph nodes

6-8 weeks

Daily visits for radiation therapy

Follow-up

Participants are monitored for safety and effectiveness after treatment, including assessment of genitourinary and gastrointestinal toxicity

Up to 5 years

Regular follow-up visits

Long-term follow-up

Participants are monitored for long-term outcomes such as distant metastasis and biochemical failure

Up to 5 years

What Are the Treatments Tested in This Trial?

Interventions

• Image-Guided Adaptive Radiation Therapy
• Stereotactic Body Radiation Therapy

Trial Overview The DAPPER Study is testing if using Stereotactic Ablative Radiotherapy (SABR) combined with daily adaptive techniques can safely target leftover tumor areas while minimizing damage to healthy tissue in men post-prostatectomy. This involves advanced imaging like MRI and PET/CT scans for precise treatment adjustments.

How Is the Trial Designed?

Group I: Group II (daily adaptive online replanning, SBRT) Experimental Treatment 6 Interventions

Patients undergo daily adaptive online replanning for SBRT to the prostate fossa and pelvic lymph nodes on study. Patients also undergo MRI and may undergo PET/CT during screening.

Group II: Group I (daily adaptive online replanning, SBRT) Experimental Treatment 6 Interventions

Patients undergo daily adaptive online replanning for SBRT to the prostate fossa on study. Patients also undergo MRI and may undergo PET/CT during screening.

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

Approved in United States as Stereotactic Body Radiation Therapy for:

• Non-small cell lung cancer (NSCLC)
• Melanoma
• Renal cell carcinoma (RCC)
• Prostate cancer
• Oligoprogressive cancers

Approved in European Union as Stereotactic Body Radiation Therapy for:

• Non-small cell lung cancer (NSCLC)
• Melanoma
• Renal cell carcinoma (RCC)
• Prostate cancer
• Oligoprogressive cancers

Approved in Canada as Stereotactic Body Radiation Therapy for:

• Non-small cell lung cancer (NSCLC)
• Melanoma
• Renal cell carcinoma (RCC)
• Prostate cancer
• Oligoprogressive cancers

Who Is Running the Clinical Trial?

Mayo Clinic

Lead Sponsor

Trials

3,427

Recruited

3,221,000+

Published Research Related to This Trial

In a study of 100 patients with early-stage non-small cell lung cancer (NSCLC) treated with stereotactic ablative body radiotherapy (SABR), the 1-, 2-, and 3-year local control rates were 100%, 93.55%, and 84.33%, respectively, indicating high efficacy in tumor control.

The treatment was associated with low toxicity, with only 2% of patients experiencing Grade-3 side effects, suggesting that SABR is a safe option for patients who are inoperable or refuse surgery.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Definitive Treatment of Early-Stage Non-Small Cell Lung Cancer with Stereotactic Ablative Body Radiotherapy in a Community Cancer Center Setting. Heal, C., Ding, W., Lamond, J., et al.[2020]

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 ablative radiotherapy (SABR) is an effective treatment for early-stage non-small cell lung cancer, especially for patients who cannot undergo surgery, showing high local tumor control rates with manageable side effects.

The CyberKnife system is particularly advantageous for SABR in lung tumors due to its ability to accurately target moving tumors during breathing, enhancing treatment precision.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

CyberKnife stereotactic ablative radiotherapy for lung tumors. Gibbs, IC., Loo, BW.[2022]

In a study of 87 men with oligometastatic prostate cancer treated with stereotactic ablative radiotherapy (SABR), the median disease-free survival (DMFS) was 21.8 months for hormone-sensitive patients, indicating a significant benefit from this treatment.

Combining SABR with short-term androgen-deprivation therapy improved both biochemical progression-free survival (bPFS) and DMFS in patients with oligorecurrent hormone-sensitive prostate cancer, suggesting a potential strategy for enhancing treatment outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Survival Outcomes and Pattern of Relapse After SABR for Oligometastatic Prostate Cancer. Mercier, C., Claessens, M., De Troyer, B., 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]

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 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]

Stereotactic ablative radiotherapy (SABR) using Cyberknife demonstrated high effectiveness in treating stage I non-small-cell lung cancer, with 2-year local control, progression-free, and overall survival rates of 91.9%, 61.7%, and 84.8%, respectively, based on a study of 153 patients.

The treatment was generally safe, with only 8.1% of patients experiencing severe toxicities, including one case of grade 5 radiation pneumonitis, indicating that while SABR is effective, careful monitoring for side effects is necessary.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Stereotactic Ablative Radiotherapy Using CyberKnife for Stage I Non-small-cell Lung Cancer: A Retrospective Analysis. Hayashi, K., Suzuki, O., Shiomi, H., et al.[2022]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC10660677/

Stereotactic body radiotherapy with CyberKnife® System ... A total of 122 patients with low- and intermediate-risk prostate cancer were treated with the CyberKnife System at a dose of 35 Gy or 36.25 Gy in five fractions ...

2. thegreenjournal.com thegreenjournal.com/issue/S0167-8140(25)X0003-7?pageStart=28

May 2025 Adoption of hypofractionation radiotherapy for localised prostate cancer and quality of life outcomes in an Australian population-based cohort

3. sciencedirect.com sciencedirect.com/science/article/pii/S2773160X25000078

The effectiveness and safety of stereotactic body ... The results show minor, non-significant differences in survival rates compared to conventional fractionation, a type of external radiation, after two and five ...

4. cancer.gov cancer.gov/news-events/cancer-currents-blog/2024/prostate-cancer-sbrt-effective-safe

SBRT Proves Effective for Some Prostate Cancers - NCI But it had to be confirmed that a 5-day course of SBRT was not worse at controlling cancer than standard radiation therapy and also that it does ...

5. jamanetwork.com jamanetwork.com/journals/jamanetworkopen/fullarticle/2723641

Long-term Outcomes of Stereotactic Body Radiotherapy for ... This cohort study of pooled individual patient data assesses long-term outcomes after stereotactic body radiotherapy for low-risk and ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC5494208/

Cyberknife Radioablation of Prostate Cancer Stereotactic ablative radiotherapy of low and intermediate risk prostate cancer patients is a safe, well-tolerated and effective treatment modality (2.25% of ...

7. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC11844808/

Current State of Stereotactic Body Radiation Therapy for ... Several phase II randomized trials have revealed that once-weekly SBRT does not seem to have superior long-term toxicity or quality-of-life profiles compared ...

8. frontiersin.org frontiersin.org/journals/oncology/articles/10.3389/fonc.2023.1270498/full

and intermediate-risk prostate cancer: clinical outcomes ... Results: The 1-, 2-, and 5-year DFS rates were 92.9%, 92.9%, and 92.3%, respectively, while the 1-, 2-, and 5-year bDFS rates were 100%, 100%, and 95.7%, ...