Stereotactic Ablative Radiotherapy for Metastatic Breast Cancer

(SABR PRIMER Trial)

Overseen By Sandy Chang

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: British Columbia Cancer Agency

Must not be taking: Cytotoxic chemotherapy, CDK4/6 inhibitors

Disqualifiers: SLE, Systemic scleroderma, IPF, others

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

Compensation: Varies

Number of Visits: Unknown

40 Participants Needed

Trial Summary

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

Yes, you will need to stop taking certain medications like cytotoxic chemotherapy, CDK4/6 inhibitors, and T-DXd during the treatment.

What data supports the effectiveness of the treatment SABR for metastatic breast cancer?

Research shows that SABR is effective for treating oligometastatic disease (cancer that has spread to a few other places) from various primary cancer sites, including breast cancer. It is a precise form of radiotherapy that delivers high doses to tumors while sparing nearby healthy organs, achieving local control rates of about 80% and potentially being 'curative' in 20-25% of cases. ^{1 2 3 4 5}

Is stereotactic ablative radiotherapy (SABR) safe for humans?

Stereotactic ablative radiotherapy (SABR) has been used to treat various types of cancer, and while it shows promise in controlling tumors, some serious complications have been reported. It's important to have strategies in place to reduce these risks. ^{5 6 7 8 9}

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

Stereotactic Ablative Radiotherapy (SABR) is unique because it is a noninvasive treatment that precisely targets and delivers high doses of radiation to small areas of cancer spread (oligometastases), which can be more effective and have fewer side effects compared to traditional radiation therapy. This approach is particularly novel for treating metastatic breast cancer, where limited prospective evidence exists. ^{1 4 5 10 11}

What is the purpose of this trial?

The study is being done to determine if stereotactic ablative radiotherapy (SABR) can control tumour growth for patients with metastatic breast cancer. Secondary objectives will be overall survival, progression-free survival and time to switch of next line of systemic therapy. Radiation-related adverse events will be assess, with a specific focus on dermatitis, lymphedema and brachial plexopathy. The exploratory objective is to correlate toxicities and outcomes with peripheral blood biomarkers and circulating tumor DNA to potentially help predict responses in future patients receiving combined therapy.

Eligibility Criteria

This trial is for individuals with metastatic breast cancer, meaning their cancer has spread beyond the original site. Participants should be candidates for radiotherapy and have measurable disease that can be targeted by SABR.

Inclusion Criteria

My breast cancer can be measured and is eligible for radiotherapy.

Able to complete patient reported outcome questionnaires

My breast cancer is confirmed as Stage IV invasive.

Exclusion Criteria

I have had radiation therapy on the same side breast before.

I do not have conditions like SLE, scleroderma, IPF, ataxia telangiectasia, and I am not pregnant.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Radiation

Participants receive stereotactic ablative radiotherapy (SABR) to the whole breast and possibly regional lymph nodes

Duration not specified

Follow-up

Participants are monitored for locoregional control, overall survival, progression-free survival, and radiation-related adverse events

2 years

Treatment Details

Interventions

• SABR

Trial Overview The study tests whether Stereotactic Ablative Radiotherapy (SABR) can control tumor growth in metastatic breast cancer patients. It also looks at how long patients live without their disease getting worse and when they might need to change treatments.

Participant Groups

Group I: Treatment Experimental Treatment 1 Intervention

SABR treatment to Whole breast +/- regional lymph nodes

Who Is Running the Clinical Trial?

British Columbia Cancer Agency

Lead Sponsor

Trials

181

Recruited

95,900+

Findings from Research

Stereotactic ablative body radiotherapy (SABR) is a feasible and well-tolerated treatment for patients with bone-only oligometastatic breast cancer, with 80% of patients successfully receiving treatment and no severe (grade 3 or 4) toxicities reported.

The treatment showed promising efficacy, with a 100% local progression-free survival (LPFS) and 67% distant progression-free survival (DPFS) at two years, suggesting that SABR could be a viable option for this patient group.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Stereotactic ablative body radiotherapy (SABR) for bone only oligometastatic breast cancer: A prospective clinical trial. David, S., Tan, J., Savas, P., et al.[2020]

Stereotactic ablative radiotherapy (SABR) is a highly effective and low-toxicity treatment for metastatic tumors, achieving local control rates of about 80%.

SABR shows promise in treating oligometastatic patients, with pilot studies suggesting it may be 'curative' in 20-25% of cases, especially when combined with systemic therapies.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

New concepts and insights into the role of radiation therapy in extracranial metastatic disease. Ricardi, U., Filippi, AR., Franco, P.[2013]

Stereotactic ablative radiation therapy (SABR) was found to be effective for treating pulmonary metastases, with a median follow-up of 23 months showing improved overall survival (OS) for patients with 3 or fewer metastases compared to those with more (74.2% vs. 59.3% at 24 months).

Patients with less responsive primary tumors (like adrenal or pancreatic cancers) had higher local failure rates, suggesting that higher doses of SABR or surgical options may be necessary for these cases to improve treatment outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Stereotactic ablative radiation therapy for pulmonary metastases: Improving overall survival and identifying subgroups at high risk of local failure. Pasalic, D., Lu, Y., Betancourt-Cuellar, SL., et al.[2021]

Stereotactic ablative radiotherapy (SABR) shows high effectiveness for oligometastatic breast cancer, achieving local control rates of 97% at 1 year and 90% at 2 years, based on a meta-analysis of 10 studies involving 467 patients.

SABR is associated with a low toxicity rate, with only 4.1% of patients experiencing grade 2 or 3 side effects, indicating it is a safe treatment option for this patient population.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Stereotactic body radiotherapy to treat breast cancer oligometastases: A systematic review with meta-analysis. Viani, GA., Gouveia, AG., Louie, AV., et al.[2021]

Stereotactic ablative radiotherapy (SABR) demonstrated a high local control rate of 91.2% for skeletal metastases in a study of 22 patients, with a median follow-up of 15.6 months, indicating its effectiveness in managing oligometastatic and oligoprogressive diseases.

The treatment resulted in significant pain control for two-thirds of symptomatic patients, with limited toxicities reported, including only two vertebral fractures and one case of grade 3 esophagitis, suggesting that SABR is a safe option for patients with skeletal metastases.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Utilization of stereotactic ablative radiotherapy in oligometastatic & oligoprogressive skeletal metastases: Results and pattern of failure. Kam, TY., Chan, OSH., Hung, AWM., et al.[2019]

In a study of 381 patients treated with stereotactic ablative body radiotherapy (SABR) for oligometastatic disease, the incidence of grade 3 or higher toxic effects was found to be less than 5%, indicating a favorable safety profile.

The rates of grade 2 or higher toxic effects were 18.6%, which is lower than the previously reported 29% in the SABR-COMET trial, suggesting that SABR may have acceptable toxicity levels and supports further research in larger trials.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Treatment With Stereotactic Ablative Radiotherapy for Up to 5 Oligometastases in Patients With Cancer: Primary Toxic Effect Results of the Nonrandomized Phase 2 SABR-5 Clinical Trial. Olson, R., Jiang, W., Liu, M., et al.[2023]

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 Radiotherapy (SABR) demonstrated a high local control rate of 90% at one year for treating oligometastatic colorectal cancer patients, with better outcomes for lesions treated with higher doses (≥ 60 Gy).

The treatment was found to be safe, with no cases of radiation-induced liver disease or severe toxicity, making SABR a viable option for patients with inoperable liver or lung metastases.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Stereotactic Ablative Radiotherapy (SABR) in inoperable oligometastatic disease from colorectal cancer: a safe and effective approach. Comito, T., Cozzi, L., Clerici, E., et al.[2022]

In a study of 85 patients with spine metastases treated with stereotactic ablative radiation therapy (SABR), the treatment demonstrated a 74.1% overall survival rate at two years and a 72.3% local control rate, indicating its efficacy in managing spinal metastases.

SABR was associated with significant pain relief, as 83.3% of patients with pre-treatment pain experienced a complete response, and the treatment showed a favorable safety profile with no severe toxicities reported.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Stereotactic ablative radiation therapy for spinal metastases: experience at a single Brazilian institution. Marta, GN., de Arruda, FF., Miranda, FA., et al.[2023]

References

1. Netherlands pubmed.ncbi.nlm.nih.gov

Stereotactic ablative body radiotherapy (SABR) for bone only oligometastatic breast cancer: A prospective clinical trial. [2020]

2. England pubmed.ncbi.nlm.nih.gov

Comparison of Single-fraction and Multi-fraction Stereotactic Radiotherapy for Patients with 18F-fluorodeoxyglucose Positron Emission Tomography-staged Pulmonary Oligometastases. [2018]

3. England pubmed.ncbi.nlm.nih.gov

New concepts and insights into the role of radiation therapy in extracranial metastatic disease. [2013]

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

Stereotactic ablative radiation therapy for pulmonary metastases: Improving overall survival and identifying subgroups at high risk of local failure. [2021]

5. Ireland pubmed.ncbi.nlm.nih.gov

Stereotactic body radiotherapy to treat breast cancer oligometastases: A systematic review with meta-analysis. [2021]

6. Australia pubmed.ncbi.nlm.nih.gov

Utilization of stereotactic ablative radiotherapy in oligometastatic & oligoprogressive skeletal metastases: Results and pattern of failure. [2019]

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

Treatment With Stereotactic Ablative Radiotherapy for Up to 5 Oligometastases in Patients With Cancer: Primary Toxic Effect Results of the Nonrandomized Phase 2 SABR-5 Clinical Trial. [2023]

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

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

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

Stereotactic Ablative Radiotherapy (SABR) in inoperable oligometastatic disease from colorectal cancer: a safe and effective approach. [2022]

10. Germany pubmed.ncbi.nlm.nih.gov

Total tumor volume as a predictor of survival in patients with multiple oligometastases treated with stereotactic ablative radiotherapy (SABR). [2023]

11. Poland pubmed.ncbi.nlm.nih.gov

Stereotactic ablative radiation therapy for spinal metastases: experience at a single Brazilian institution. [2023]