The oligometastatic state in breast cancer: hypothesis or reality

The term 'oligometastasis' was initially used to describe a restricted locoregional tumour load, but the term has now become synonymous with isolated distant metastases. The existence of an oligometastatic state is still not widely recognised in the management of breast cancer patients. However, there are a number of patients who do develop isolated metastases and in whom long term survival can be achieved following appropriately targeted treatment. This review article discusses the possible biological mechanisms behind the development of an oligometastatic state and the findings from different trials which describe results following radical therapy for isolated metastatic disease. Although no large scale trials in this area have yet been undertaken, there is evidence to support the existence of an oligometastatic state in patients with breast cancer and we discuss the appropriate management for this clinical scenario.