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

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.