Does Radiotherapy Have Curative Potential in Metastatic Patients? The Concept of Local Therapy in Oligometastatic Breast Cancer

In 1995, Hellmann and Weichselbaum defined for the first time the term oligometastases which is used to describe limited metastasis with a maximum of 3-4 clinically detectable metastases. It is assumed that these patients have a better prognosis and that local treatment of the metastases plays a significant part in the further development of the disease. Therefore, these patients could benefit from a curative local therapy of the manifested metastases. Local therapy measures include mainly radiotherapeutic methods alongside invasive ablative processes, such as surgical resection and radiofrequency ablation. Patients subjected to radiation therapy benefit especially from the usage of modern precision technology as it reduces the radiation exposure to the normal tissue, and because short radiation sessions with escalating doses are possible (e.g. radiation surgery, image-assisted radiation therapy, stereotactic radiation). Initial clinical studies show very good local tumor control rates which are on a par with resection and ablative methods, but with very few side effects and risks. This article summarizes the integration of the concept of oligometastases in the radiotherapy of limited metastatic breast cancer.