Stereotactic Ablative Radiotherapy for OligoMetastatic Breast Cancer

TAORMINA is an international, multicentre, randomised phase 3 trial for patients with oligometastatic breast cancer (OMBC) that will be allocated to combined stereotactic ablative radiotherapy (SABR) + systemic therapy (investigational arm) versus systemic therapy alone (control arm) as 1st line therapy. Patients with 1-5 metastases in 1-2 organs (confirmed by PET-CT) with any breast cancer subtype can be enrolled. All metastases must be available for SABR. The primary aim is to investigate if the addition of SABR to the oligometastatic sites in addition to the standard first-line treatment can improve progression-free survival (PFS). Secondary aims are to compare overall survival (OS), response rate and time to development of new lesions, acute and late toxicity. quality of life, time to start of chemotherapy (luminal patients). Exploratory analyses: Circulating tumour DNA as an early sign of disease progression. Immun panel for determination of the effect of SABR on patients´ immune response. To investigate the survival for each BC subtype (Luminal, HER2+ and TNBC). To investigate survival in patients with de novo OMBC and recurrent OMBC respectively. Stratifications are based on subtype (luminal, HER2-positive vs TNBC) and type of OMBC (de novo vs. recurrent) without formal sample size calculation for the stratification factor (exploratory analysis). Patients with de novo metastatic OMBC that is planned for neoadjuvant treatment are recommended to complete treatment followed by standard surgery and radiotherapy or SABR towards the primary tumour lesion(s).