The goal of this clinical trial is to assess Stereotactic Ablative Radiotherapy (SABR) as a method to delay a change in systemic therapy in patients with oligoprogressive ER-positive, HER2-negative advanced breast cancer. The main question it aims to answer is to assess whether the addition of SABR to continuation of first line endocrine therapy and CDK 4/6 inhibitor (Arm A) to patients with oligoprogressive ER-positive, HER2-negative advanced breast cancer could have longer time to strategy failure (TSF) in comparison to physician choice of systemic treatment (Arm B) in patients who had progressed first line. The treatment strategy in Arm A is to maintain patients on current endocrine therapy and CDK 4/6 inhibitor, controlling localised progressing sites of disease with SABR. Treatment strategy in Arm B is to maintain disease control with physician's choice of systemic therapy alone.
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Primary Outcome Measure
Timeframe: Time from randomisation to progression of disease resulting in a failure of treatment strategy or death by any cause assessed until withdrawal of consent, death, or 3 years after the last patient has been randomised, whichever is earlier.