Primary Breast Oligoprogressive Sites Treated With Radiotherapy to Obviate the Need to Change Systemic Therapy (BOSS)

September 2, 2026 updated by: Mayo Clinic

Primary Breast Oligoprogressive Sites Treated With Radiotherapy to Obviate the Need to Change Systemic Therapy (BOSS)

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

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Detailed Description

PRIMARY OBJECTIVE:

I. To assess whether radiotherapy can provide clinically significant freedom from a change in systemic therapy (defined as for at least 6 months) for well-selected patients with oligoprogressive metastatic breast cancer.

OUTLINE: This is an observational study.

Patients undergo blood sample collection and complete questionnaires on study.

Study Type

Interventional

Enrollment (Actual)

45

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Arizona
      • Scottsdale, Arizona, United States, 85259
        • Mayo Clinic in Arizona
    • Minnesota
      • Rochester, Minnesota, United States, 55905
        • Mayo Clinic in Rochester

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Study Population

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

Description

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.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Metastatic Breast Cancer
Breast cancer patients with ER+/PR± (any PR status)/HER2- disease or HER2+ disease (any ER or PR status) will receive radiotherapy that consists primarily of Stereotactic body radiation therapy (SBRT), but at a minimum, it will consist of dose-escalated, moderately hypofractionated radiotherapy (as opposed to conventional fractionation or conventional palliative treatment regimens).
Procedure: Biospecimen Collection
Undergo blood sample collection
Other Names:
  • Biological Sample Collection
  • Biospecimen Collected
  • Blood Sample Collection
Other: Surveys
Patients complete the European Quality of Life 5 Dimensions 5 Level Version (EQ-5D-5L) survey and "Was it Worth It" questionnaire.
Radiation: Stereotactic Body Radiation Therapy (SBRT)
Patients receive stereotactic body radiation therapy (SBRT), metastasis-directed radiation therapy .
Other Names:
  • SBRT
  • stereotactic body radiation therapy
  • SABR
  • Stereotactic Ablative Body Radiation Therapy
Procedure: Computed Tomography
Undergo CT, MRI and/or PET/CT
Other Names:
  • CT
  • CAT
  • CAT Scan
  • Computed Axial Tomography
  • Computerized Axial Tomography
  • Computed Tomography (CT) scan
Procedure: Magnetic Resonance Imaging
Undergo CT, MRI and/or PET/CT
Other Names:
  • MRI
  • Medical Imaging, Magnetic Resonance / Nuclear Magnetic Resonance
  • MR
  • MRI Scan
  • NMRI
  • Nuclear Magnetic Resonance Imaging
  • Magnetic Resonance Imaging (MRI)
  • sMRI
  • Structural MRI
Procedure: Positron Emission Tomography
Undergo CT, MRI and/or PET/CT
Other Names:
  • Medical Imaging, Positron Emission Tomography
  • PET
  • proton magnetic resonance spectroscopic imaging
  • PT
  • Pet Scan

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Freedom from a change in systemic therapy (FCST) - overall
Time Frame: 6 months
FCST is defined as no change in systemic therapy at 6 months after radiotherapy and patient survival at 6 months after radiotherapy. Treatment failure would indicate that there is no longer stability of systemic therapy (and thereby requires a change in systemic therapy to a different agent).
6 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Freedom from a change in systemic therapy (FCST) - ER+/PR±/HER2- (Subgroup A)
Time Frame: 6 months
Will assess whether metastasis-directed radiotherapy can result in a clinically significant FCST (defined as for at least 6 months) for patients with estrogen receptor+/progesterone receptor±/human epidermal growth factor receptor 2 negative (ER+/PR±/HER2-) disease. The frequency and percentage for FCST rate will be reported, including the 95% confidence interval.
6 months
Freedom from a change in systemic therapy (FCST) - HER2 (Subgroup B)
Time Frame: 6 months
Will assess whether metastasis-directed radiotherapy can result in a clinically significant FCST (defined as for at least 6 months) for patients with human epidermal growth factor receptor 2 positive (HER2+) disease. The frequency and percentage for FCST rate will be reported, including the 95% confidence interval.
6 months
Progression-free survival (PFS)
Time Frame: Up to 5 years
Will assess the impact of metastasis-directed radiotherapy on PFS in the setting of oligoprogressive breast cancer. PFS is defined as the time from completion of radiotherapy to the first of either disease progression or death from any cause. Medians and 95% confidence intervals will be reported.
Up to 5 years
Overall survival (OS)
Time Frame: Up to 5 years
Will explore the impact of metastasis-directed radiotherapy on overall survival (OS) in the setting of oligoprogressive breast cancer. OS is defined as the time from completion of radiotherapy to death from any cause. Medians and 95% confidence intervals will be reported.
Up to 5 years
Quality of life - EQ-5D-5L
Time Frame: Up to 5 years
The EuroQol 5 Dimension 5 Level (EQ-5D-5L) is a patient-reported outcome measure used to assess health-related quality of life across five dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety/depression. Each dimension is rated on a score of 1-5 where 1=no problems, 2=slight problems, 3=moderate problems, 4=severe problems, and 5=extreme problems/unable to perform the task. EQ-5D-5L index scores range from -0.59 to 1, where 1 is the best possible health state.
Up to 5 years
Determine the local control of irradiated, oligoprogressive lesions
Time Frame: Up to 5 years
This rate will be reported as a percentage with a 95% confidence interval.
Up to 5 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Mayo Clinic

Investigators

  • Principal Investigator: Roman O. Kowalchuk, MD, Mayo Clinic in Rochester

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

October 23, 2023

Primary Completion (Estimated)

October 26, 2026

Study Completion (Estimated)

August 6, 2031

Study Registration Dates

First Submitted

September 20, 2023

First Submitted That Met QC Criteria

September 26, 2023

First Posted (Actual)

September 28, 2023

Study Record Updates

Last Update Posted (Actual)

September 3, 2026

Last Update Submitted That Met QC Criteria

September 2, 2026

Last Verified

September 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • GMROR2232 (Other Identifier: Mayo Clinic Radiation Oncology)
  • NCI-2023-03208 (Registry Identifier: CTRP (Clinical Trial Reporting Program))
  • 22-002943 (Other Identifier: Mayo Clinic Institutional Review Board)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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