Patients will receive single-dose preoperative radiotherapy followed by breast conserving surgery (BCS) at 12 months after radiotherapy, as long as follow-up MRI scans show a complete radiologic response. In case of incomplete radiologic response, BCS will be performed at 6 months after radiotherapy. BCS is performed earlier when progressive disease is found on MRI. In the follow-up period between radiotherapy and surgery, tumor response will be monitored using MRI every 3 months. After surgery, patients will be followed up until 10 years after radiotherapy treatment to assess oncological outcomes, toxicity, cosmetic outcome and quality of life.
In this ABLATIVE-2 trial, low-risk breast cancer patients will be treated with MRI-guided single dose preoperative partial breast radiotherapy to assess the rate of pathologic complete response after an interval of six to twelve months between radiotherapy and surgery. Response monitoring will be assessed using MRI and markers in blood and tumor tissue to enable prediction of pathologic response.