STEREO-SEIN: Trial of Superiority of Stereotactic Body Radiation Therapy in Patients With Breast Cancer

The previous reported phase I study allows us to prospectively define the optimal total dose in different metastatic locations (88). However, several questions are still unanswered such as the adequate timing of the stereotactic body radiation therapy (SBRT) in oligometastatic disease. Indeed, there are two different oligometastatic states: "de novo", i.e. occurring at first metastatic presentation without any previous systemic therapy; and "secondary", defined as residual disease after systemic treatment.

The investigators wish to prospectively study the role of metastases SBRT with curative intent in de novo oligometastatic disease.

This clinical trial would be the first randomized study studying SBRT at onset of the metastatic disease. If this trial shows a PFS improvement, it will definitively change the standard of treatment and it will highlight SBRT as a key treatment of metastatic disease. It will confirm the oligometastasis hypothesis as well as the Simon Norton hypothesis (92).