Management of brain metastases: history and the present

Brain metastases are significant causes of morbidity or mortality for patients with metastatic cancer. With the application of novel systematic therapy and improvement of overall survival, the prevalence of brain metastases is increasing. The paradigm of treatment for brain metastases evolved rapidly during the last 30 years due to the development of technology and emergence of novel therapy. Brain metastases used to be regarded as the terminal stage of cancer and left life expectancy to only 1 month. The application of whole brain radiotherapy for patients with brain metastases increased the life expectancy to 4-6 months in the 1980s. Following studies established surgical resection followed by the application of whole brain radiotherapy the standard treatment for patients with single metastasis and good systematic performance. With the development of stereotactic radiosurgery, stereotactic radiosurgery plus whole brain radiotherapy provides an alternative modality with superior neurocognitive protection at the cost of overall survival. In addition, stereotactic radiosurgery combined with whole brain radiotherapy may offer a promising modality for patients with numerous multiple brain metastases who are not eligible for surgical resection. With the advancing understanding of molecular pathway and biological behavior of oncogenesis and tumor metastasis, novel targeted therapy including tyrosine-kinase inhibitors and immunotherapy are applied to brain metastases. Clinical trials had revealed the efficacy of targeted therapy. Furthermore, the combination of targeted therapy and radiotherapy or chemotherapy is the highlight of current investigation. Advancement in this area may further change the treatment paradigm and offer better modality for patients who are not suitable for surgical resection or radiosurgery.