NCT06055881 · Mayo Clinic
Primary Breast Oligoprogressive Sites Treated With Radiotherapy to Obviate the Need to Change Systemic Therapy
(BOSS)
What this study is about
This study assesses if metastasis-directed radiation therapy (Stereotactic body radiation therapy - SBRT) can delay a change in systemic therapy, and if circulating tumor cells in the bloodstream can help guide treatment options in metastatic breast cancer patients with progressive disease
View original scientific description
This study assesses if metastasis-directed radiation therapy (Stereotactic body radiation therapy - SBRT) can delay a change in systemic therapy, and if circulating tumor cells in the bloodstream can help guide treatment options in metastatic breast cancer patients with progressive disease
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Age ≥ 18 years.
- Histological confirmation of primary breast cancer.
- Patients with metastatic breast cancer and at least 12 months of clinical response to first-line systemic therapy, with the subsequent development of 1-3 extracranial sites of oligoprogressive disease, and who plan for the continuation of the current systemic therapy.
- NOTE: patients with de novo metastatic disease and those developed metastatic disease after initially localized disease can both be included. OR
- Patients with metastatic breast cancer and at least 6 months of clinical response to second-line systemic therapy (or further, e.g., third- or fourth-line), with the subsequent development of 1-3 extracranial sites of oligoprogressive disease.
- Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) ≤ 2.
- Negative urine or serum pregnancy test done ≤ 7 days prior to registration, for women of childbearing potential only.
- Ability to complete questionnaire(s) by themselves or with assistance.
- Provide written informed consent.
- Willing to return to enrolling institution for follow-up (during the Active Monitoring Phase of the study).
- Willing to provide blood samples for correlative research purposes.
- Receiving radiation therapy as specified in the protocol.
Exclusion criteria
- Male patients.
- Nursing or pregnant women.
- Men or women of childbearing potential who are unwilling to employ adequate contraception.
- Patients with triple negative disease (negative for ER, PR, and HER2).
- Active second primary malignancy
- More than 3 extracranial sites of oligoprogressive disease
- Active CNS disease. Patients with asymptomatic and stable, treated CNS lesions (radiation and/or surgery and/or other CNS-directed therapy who have not received corticosteroids for at least 4 weeks) are allowed.
- Active connective tissue disease that is felt by the treatment team to pose an excess risk of toxicity.
- Prior radiation that overlaps with the intended treatment volume such that, in the opinion of the patient's Radiation Oncologist, radiotherapy to progressing sites will not be safe.
- NOTE: patients with some dose overlap with prior radiotherapy that is deemed safe by the patient's Radiation Oncologist can be included in the trial.
Where
- Scottsdale, Arizona
- Rochester, Minnesota
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Feb 6, 2026 · Source of record for eligibility and locations