Abstract
Synchronous metastatic breast cancer accounts for 5 to 6% of all breast cancers in Western countries, which corresponds to nearly 2500 new cases per year in France. Irradiation of the primary tumour in cases of metastatic disease at diagnosis was historically reserved for palliative indications. However, progress in systemic treatments, a better understanding of the biological basis of metastatic dissemination, the genesis of the concept of oligometastatic disease and ablative treatments directed towards metastases are revolutionizing the management of patients with de novo stage IV breast cancer. Survival of these patients has improved markedly over the years, and several studies have investigated the carcinological benefit of local treatment of the breast tumour in patients with advanced diseases at diagnosis. This article provides an update on the role of irradiation of the primary tumour in breast cancer with synchronous metastases, and discusses its interest through published or ongoing trials.